First tests: Seems to be working fine when using the classic WikiEditor (2010) and I think there's no VisualEditor wikitext editor (2017) available. So the issue might be with certain images only...

What I did:

• Login to Commons
• Enable the QInominator Gadget on https://commons.wikimedia.org/wiki/Special:Preferences#mw-prefsection-gadgets
• Go to a random picture https://commons.wikimedia.org/wiki/Special:Random/File
• Click Nominate this image for QI

• Accept the text prompt
• Go to the nomination page https://commons.wikimedia.org/wiki/Commons:Quality_images_candidates/candidate_list
• Edit the page and click on

• Wiki text is added to the editor and can be reviewed with Show changes

Note: Don't save if here you don't want to mess up things :-).

Seems, there's an issue when using syntax highlighting. :-)

There's a MediaWiki-extensions-CodeMirror fallback for inserting nominations that could be reviewed on the beta cluster. See https://commons.wikimedia.beta.wmflabs.org/w/index.php?title=MediaWiki%3AQIvoter.js&diff=290922&oldid=290825

I updated the patch to also include the 2nd place where changing the textbox content might be relevant. This is mainly affecting the QIvoter part of the script. The voter part would need way more love though it seems so I stopped with the main issue fixing the QInominator.

https://commons.wikimedia.beta.wmflabs.org/w/index.php?title=MediaWiki%3AQIvoter.js&diff=290947&oldid=290825

Can be tested on the beta cluster. Browse random files, add them to your "bucket" and then edit https://commons.wikimedia.beta.wmflabs.org/wiki/Commons:Quality_images_candidates/candidate_list and them there with the green button.

I left a note on the QIvoter Gadget help page with a hint to the syntax highlighting incompatibility. https://commons.wikimedia.org/w/index.php?title=Help%3AGadget-QIvoter&diff=784687663&oldid=130861000

Handover for further working on this: If the code seems fine, an interface admin could copy the code from https://commons.wikimedia.beta.wmflabs.org/wiki/MediaWiki:QIvoter.js to https://commons.wikimedia.org/wiki/MediaWiki:QIvoter.js to deploy it. I saw @Lucas_Werkmeister_WMDE editing that file in the history. ;-)

Done, though an edit request is usually the better way to get the attention of interface admins.

Thank you @LucasWerkmeister! 🎉