Interesting Mark, I’ve never seen that. That suggests there may be a problem with PL2 updating its database and getting hung somewhere. Leaving the folder commits all of the edits to your sidecar files, and when you return, they are as you expected.
Late last night I had the idea there might be a cache problem here, so I cleared all the cache (which was 610MB out of 1GB) and set it to zero. That may fix the problem. We shall see!