Originally Posted by exaltedwombat
So it's a "Sigil is right, B & N are wrong" standoff? :-)
In this case: 'Maybe'
Each tool has its know quirks
EPUB check Misses many errors (and can be vague on some it does find).
B&N is wrong relying on a Single tool to Automatically 'Reject' submissions.
IMHO if the tools don't agree (one passes, the other fails) A human should review the results (Usually take just a few minutes looking , just to say Yay or Nay )