Nothing has seemed to help this so far. I did manage to get it up to date the last time I posted here, but I tried to refresh it recently and no matter what I do (including re-installing it a couple of times), it won't update correctly. One thing it did before that made it still workable, is that it would highlight films as appearing in a list even if it didn't use the correct colour to highlight it. Now, it's skipping films entirely so they have no highlight at all. Ugh, IMDb why do you have to be so complicated...

I get a lot less errors now: https://pastebin.com/9nhaki12. I checked about 5 of them and they were all some of my longer lists.

It doesn't take very long to update, maybe 10 seconds?

Hm, it says I had 197 lists on my list page, but then also my watchlist and ratings must count for a couple more, so I wonder what extra lists it's reading. I deleted a bunch of list so it now says I have 157, but it still doesn't appear to be refreshing correctly. Without my custom colours, it seemed to highlight everything correctly, but when I added them back, the 'Lists' colours didn't highlight and when I refreshed, neither did the ratings. Could the length of lists be an issue? My ratings are about 8,500 films so I wonder if the increasing number could be a problem.

And yeah, I only use IMDb out of convenience for their URLs, their customer support and 'updates' are pathetic so I don't think it's worth contacting them.

I'll to check in more regularly, totally forgot last time, apologies.

Here's the pastebin with all the errors (they're all export and downloading errors): https://pastebin.com/kL0P7fF7

Are you changing the script source code to add custom colors?
Yes, I use these custom colours:

  customColors["Your ratings"]   = "Green";
  customColors["OnLists"]   = "MidnightBlue";
  customColors["NotonLists"]   = "PaleVioletRed";
  customColors["DefaultColor"]   = "DeepSkyBlue";

I've been using this script since IMDb actually had 'MyMovies', and as soon as we could make lists I used these custom colours. I've had no issues until the last year or so, but usually after a few refreshes it would all be good though I've had increasing difficulty getting them to refresh correctly.

Does color highlighting works with the original (unmodified) script code?
The watchlist and the default colour work, but only some of my rated films do not get highlighted.

When you don't change the code, or after you do a change (but NOT between two changes!), does highlighting behaves consistently the same way after you refreshes the data? Or does it behave differently (without you changing the code) when refreshing a couple of times?
When I do change the code, it behaves completely differently. With the original code, sometimes my rated films are highlighted, sometimes none are, and sometimes different ones are.

So apparently there's not enough space to post it all. I had 106 errors and 33 warnings. How should I share these?

A follow-up to my previous post... I didn't check here for a few weeks and when I came on my issue was closed so I just left it for a while, but since I'm still having problems, here's the errors and warnings from the javascript console:

Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
Invalid URI. Load of media resource failed. 2 www.facebook.com
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 2 background.js:1
Error: WebExtension context not found! 3 ExtensionParent.jsm:1089:13
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. recent:771:1
XML Parsing Error: not well-formed
Location: https://userstylesapi.com/tic/stats
Line Number 1, Column 1: stats:1:1
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. static-age:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Error: Frame not found, or missing host permission undefined
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. static-age:3307:1
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. f♯a♯∞:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Error: Frame not found, or missing host permission undefined
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 2 background.js:63
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. f♯a♯∞:2740:1
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. buena_vista_social_club:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Error: Frame not found, or missing host permission undefined
XML Parsing Error: not well-formed
Location: https://userstylesapi.com/tic/stats
Line Number 1, Column 1: stats:1:1
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. homogenic:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Error: Frame not found, or missing host permission undefined
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. buena_vista_social_club:4406:1
XML Parsing Error: not well-formed
Location: https://userstylesapi.com/tic/stats
Line Number 1, Column 1: stats:1:1
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. homogenic:5168:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 3 background.js:63
XML Parsing Error: not well-formed
Location: https://userstylesapi.com/tic/stats
Line Number 1, Column 1: 2 stats:1:1
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
Promise resolved after context unloaded
inject.js:107
Promise resolved after context unloaded
promisify.js:13
Promise resolved after context unloaded
polyfill.js:231
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 5 background.js:63
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. portishead:1:1
Error: Frame not found, or missing host permission undefined
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 8 background.js:63
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. portishead:3548:1
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. mogwai_young_team:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Promise resolved after context unloaded
include.preload.js:549
Promise resolved after context unloaded
injected.js:1
Promise resolved after context unloaded
promisify.js:13
Error: Frame not found, or missing host permission undefined
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
Promise resolved after context unloaded
inject.js:68
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
Promise resolved after context unloaded
inject.js:68
Loading failed for the with source “https://global.proper.io/rateyourmusic.min.js”. vessel:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Error: Frame not found, or missing host permission undefined
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. mogwai_young_team:3465:1
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
NS_ERROR_NOT_INITIALIZED injected.js:1
Promise resolved after context unloaded
inject.js:68
Loading failed for the with source “https://e.snmc.io/2.5/js/web_ads/advertisement.js”. vessel:2302:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
XML Parsing Error: not well-formed
Location: https://userstylesapi.com/tic/stats
Line Number 1, Column 1: 3 stats:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 4 background.js:63
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
Promise resolved after context unloaded
inject.js:68
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 8 background.js:63
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
Promise resolved after context unloaded
inject.js:68
Error: WebExtension context not found! 2 ExtensionParent.jsm:1089:13
Promise resolved after context unloaded
inject.js:68
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 5 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 3 background.js:1
[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowUtils.removeSheet]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://gre/modules/ExtensionCommon.jsm :: runSafeSyncWithoutClone :: line 65" data: no] 3 ExtensionCommon.jsm:65:12
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 2 background.js:1
Error: WebExtension context not found! 3 ExtensionParent.jsm:1089:13
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
XML Parsing Error: not well-formed
Location: https://userstylesapi.com/tic/stats
Line Number 1, Column 1: stats:1:1
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. 3 background.js:1
Content Security Policy: Ignoring ‘x-frame-options’ because of ‘frame-ancestors’ directive.
Unchecked lastError value: Error: Could not establish connection. Receiving end does not exist. background.js:63
Ignoring unsupported entryTypes: paint. ls048608434:17056:161
No valid entryTypes; aborting registration. ls048608434:17056:161
Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience. For more help http://xhr.spec.whatwg.org/ other-2462493501.CB463665613.js:1:19158
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://images-na.ssl-images-amazon.com/images/G/01/imdbads/custom/test/index/js/show_ads.js. (Reason: CORS request did not succeed).

Whenever I refresh my ratings/lists, I find that it leaves out some of my custom colours. For example, I have my ratings, plus a list of films on iCM and a list of films that aren't. When I refresh it often just highlights the titles as 'appearing on a list' with the bold blue, then I refresh again and it'll be the bold blue + green for rated films. I usually have to uninstall and reinstall the script for it to take into account all the lists again.

IMDb has made another bunch of awful, useless 'updates' and therefore this amazing script no longer works (though retains the old info).