Looking at the DT site, My Files---->Online files sorted by Without Additional looks like Stock Submitter sometimes doesnt upload the additional files. Looks like the problem started January 2021? I have a few hundred.
Anyway, thought I should post so others can check if they have the same issue.
EDITED TO ADD: I tracked down some of the files in StockSubmitter. All show as submitted and are correctly paired eps10/jpeg
EDIT 2: Niakris, is there a way to force upload of just the additional file? doing this through DT's site is taking forever.