[Ardour-Users] Ardour 5.5 session always in "unsaved" state

[George Khouri]

Friends,
I have a session in which, all-of-a-sudden, Ardour 5.5 always 
thinks/says it needs saving, even after being saved. I couldn't find any 
discussion of this problem elsewhere.  I have worked in this session 
daily for a few weeks, and I have saved several snapshots. All has been 
normal regarding the "save" state.  Yesterday I saved a new snapshot, 
switching to the new snapshot. From that point, in this snapshot and the 
one it was created from, the session always says it needs saving when I 
close it. If I modify the session, File->Save will save the changes but 
Ardour thinks the session is not saved.  The asterisk is always in the 
main window title bar, and I can't quit Ardour without being prompted to 
save the session. Annoying and unsettling. Earlier snapshots of the same 
session open fine and the saved/unsaved state indicators behave as 
expected.
Other Ardour sessions and new sessions behave as expected regarding 
saved/unsaved state indicators.
Running on Ubuntu Studio 14.04

Any ideas? I'd rather not go back to an earlier snapshot, since I would 
lose several hours of editing.
Thanks,
George Khouri