When editing a collection, it opens and all the added items have the check mark disabled.
It should be green (enabled) because the items are added.
Check out demonstration gif (reproduced with latest chrome on beta cluster Jun 23 14:30 CEST):
Diving into the css you can see that they actually have the class mw-ui-icon-tick-disabled on them, so it seems like it is a JS regression and not a CSS one.
It would be great to see if we can get this fixed before branch cut.