I have been getting occasional IDE freezes for a few months now, with latest IDE and at least one older IDE version.
It only happens when I'm working in B4A. The cursor goes 'busy' and windows become unresponsive.
After 5 to 10 seconds, everything goes back to normal.
Are you using a laptop with a spinning rust disc? Normally Auto Backup is quite quick but if a laptop spins down the disc to save power you may be seeing the spin-up delay as the disc comes up to operating speed before it can be written to.