An owner of one of our lists tried to PUT it.  The only errors I could find
in the console were
 
From (own): PUT listname LIST PW=listpassword
To   (own): The following problems have been detected in the list header: (...)
To   (own): PUT operation rejected, old list remains unchanged.
 
The error wasn't specified - only the ellipses (...) was there.
Only difference I could see was that MAIL-VIA was changed from DIST2 to
DIST and several owners were changed.