By default, Airwave does daily Audit (can be editable). Is Audit enabled to switch group? If so, with daily audit, if there's config difference, there will be auto backup taken.
The default backup doesn't happen with every change. If audit is enabled and the backups doesn't happen, there needs to be a TAC case to check.
On Demand backup us manual to collect the backup as and when needed.
------------------------------
Regards
Gowri Amujuri
------------------------------