Strange issue with Time Machine.

[Lufbrarunner]

my M2 Mac mini is set up to do Time Machine backups to 2 external 2gb drives and a 3gb Time Capsule. This morning the first back halted with a message that it had failed to complete and then I tarted getting occurrences of Time Machine drives being mounted, 30+ before I closed down the computer and rebooted. After the reboot everything went back to normal and the backups completed without incident. Any thoughts or suggestions as to the cause?