I already tried to report it here https://secure.phabricator.com/T13402, but it got nuked together with discourse :). So here I am, few years later, reporting same thing :).

When Owners package is set to Audit Commits With No Owner Involvement and such commit lands, it is not triggered for audit (but is added into owners package commit log)

It is, because on this one line of code, there should be return false instead of return true.
https://we.phorge.it/source/phorge/browse/master/src/applications/repository/worker/PhabricatorRepositoryCommitPublishWorker.php$330

If there is no revision, owner is not involved (exactly as comment couple lines higher says) -> return false.
This used to be a part of shouldTriggerAudit method (thats why there is return true), but it was moved into isOwnerInvolved method, where it should be negated.
But it is still the same as was in shouldTriggerAudit.

Should be easy fix, making Owners package audit working again :).

Thanks for looking into this.