I've seen this as well, and when I go to the Tracks view and sort by Date Modified it doesn't show any files as being updated. Like right now when I run a scan it says 36 updated every time, but when I look in the tracks view the most recent file that was updated was from 2 days ago. I have made a decent amount of changes to the library recently.
The only way I've been able to get rid of it is by create a temporary library and doing a fresh scan of my music folder, and then replacing the mbl file in my library with the clean one I just created in the temporary library.