The little icons to the left of a project tend to fill up as more items are added.
I use one project as an inbox for filing into other projects. After I’ve filed all the items, and the project is again empty, the project icon in the list to the left stays full.
Can you have the project icon reset when the project is empty?
Great to see you noticed the detail @TimTCM, can I ask how you clear the project? By moving notes to a different project or by deleting them? If the latter, the icon should reset itself if you empty the Bin.
I’ve also noticed issues with items in the trash. Links, overviews, calendar which are a few that I’ve experienced. This is not a new thing. The trash needs to somehow be more isolated.