[Lawrie]

Hi Mike,
display settings:
dim nav bar = off
hide nav bar = off (I use the nav bar features frequently, and the glitch with having to sometimes double tap things when it's on is too distracting)
fullscreen mode = off (I like having the clock and battery state visible, as well as quick access to changing Android settings)

With the settings as above, if I crop a song, then return to the normal display the lower part of the song encroaches, or crosses the lower screen border (the top of the nav bar), but I can scroll it up (the top now goes off the top edge) and down.  If I then return to the library screen and reopen the cropped song (reload the song) it appears as it should with the cropped bottom of the song displaying as I expected it should and I can no longer scroll it up or down.

I was first alerted to the problem when songs cropped in 3.8.14 didn't display properly after the upgrade, but I'm not sure what sequence of events revealed it.  I've tried confirming this in other cropped songs from other libraries and there is no indication of a problem until I enter and exit the crop screen.  Thinking about it, it is likely I was doing an annotation (VS indication) and needed to change the crop boundary to have room for it.

I hope this is helpful, I don't really have facilities to video things but if it becomes necessary I'm sure I can work something out, it just may take a while.  Perhaps there is a screen recording app I can use?

PS re-reading your point 3 above I wonder if your fix for that issue might not fix my problem too.  I seems to me that changing display settings happens when entering and exiting the song overlay, though that alone is not enough the cause the crop issue, I actually have to enter the crop screen for that to happen.