Quick Fix: Change your power plan and disable sleep mode (or greatly extend the timeout for it) on connected to power & to what you can tolerate on battery, understanding this will impact battery life for the latter.
This seems to prevent the bug from triggering.
Note - I have zero issue like this on my M1 Mac that does NOT have Cisco VPN installed. (Both are M1's, one's a pro and one's an air since I didn't need the extra GPU.)