by Ken Task.
Ok, got it. this thread, however, was about temp/backup dir and consuming a lot of space ... your issue with what changes to a course qualifies it to include the course in auto backups ... similar but maybe not the same.
There are task now part of or will replace cron jobs ... one of those task is automatted backups (schedule) so there are two places one needs to check ... automatted backups and the related task.
With automatted backups off and the task set to disabled as well ... there shouldn't be any activity in moodledata/backup/temp/ for autobackups or any backups *unless* a teacher or administrator backed up a course manually. So wait past the next schduled autobackup on your system, then check moodledata/temp/backup/ for .log files ... 0 byte log files are good ... backups completed successfully. Anything remaining ... investigate.
I also have wondered about changes to a course and how Moodle then determines to include that course in it's autobackups. Tinkered with it some ... never did figure it out. Too small a change meant nada ... So guess we are all gonna have to wait for this discussion/cussion to attract attention or someone will file something in tracker.
'spirit of sharing', Ken