This shouldn't really do anything with a note history settings
It has everything to do with note history settings. If you have hisory on then even if the note itself has been deleted the revisions remain in the database to allow for recovery. If those notes have associated resources then they will not be deleted.
If you have note history set to 0 and delete a note then it will (I think after a short time span) delete the note, all of its revisions (if it had any) and its resources.
If you have proof that it is not behaving in the above manner then it sounds like an actual issue to be investigated.
Just to note, that I had tried then to set a Note History to Zero, yet all previously saved revisions, had been kept intact, even all notes had been already deleted
I think there is a tidy up routine or something similar (please somebody correct me if I'm talking out my behind) that should clear up the unused resources on a schedule.