I don't know if this is a feature or a bug but AWB requires users to relogin every couple hundred edits. Its possible this is by design in which case feel free to close this ticket but just in case this was an unintentional glitch I wanted to mention it.
After asking several people who use AWB on EN no one has noticed this problem so I think this is only occurring on Commons. Also, the exact error message is a popup that says:
Logged off You have been logged off due to loss of session data. Please relogin.
This has nothing to do with the API beyond the fact that the API is being used.
Looking at AWB's source code, I don't see the exact message quoted. I do see "You've been logged off, probably due to loss of session data.", which among other times appears when AWB receives a 'badtoken' error. This is incorrect behavior, BTW: it should be loading a new token and resubmitting the action rather than claiming the user has been logged off.
The portion of this bug due to MediaWiki or Wikimedia's setup is very likely a direct dup of T102199.
Yes, so when AWB gets the badtoken error from the API we ask the user to log in, but we don't need the user to log in, we can just process the page again (same behaviour as having a timeout error). rev 11269 corrects that. So resolved from AWB perspective.