External Drives in Monterey
I'm seeing rumblings that I'm not the only one here...mid-2015 MBP and upgraded to Monterey and immediately after upgrade my external USB drive (Time Machine) and SD card (in the lost) periodically unmount themselves, give a warning and then randomly remount. This makes these external storages unusable- Time Machine won't even engage in the updated, current state.
MacBook Pro 15″, macOS 12.0