Issue with Emoji Button: After editing or adding custom emojis, some users are experiencing a bug where clicking the emoji button results in a faded screen without the emoji selector pop-up appearing. This issue has been reported in Chrome and Firefox. Chili and DavidGNavas encountered the problem after deleting or adding custom emojis, and DavidGNavas shared an error log showing an “Uncaught TypeError” related to reading property ‘icons’ of undefined. A possible solution involves clearing browser cache. The issue is under investigation, and a potential fix has been identified in a GitHub commit.
Continuing the discussion from Emoji selector and custom Emoji:
Continuing the discussion from Emoji selector and custom Emoji:
This pops up in the logs each time:
Uncaught TypeError: Cannot read property 'icons' of undefined
Url: http://[forumname].com/assets/application-773b3193b8dbe0047709e10f69a9bc8e.js
Line: 10
Column: 69
@zogstrip can you have a look at this?
Thanks for reporting that. 
The issue would only happen if you refresh the page and the last group you used was the custom group.
https://github.com/discourse/discourse/commit/66882155f0fbcfe8b8ac89a8f8c91999d32c63d4