Backup of library to use as distribution to other tablet hung several times. Finally seemed to work and I got them restored into tablets. Had to shut MSP Companion down a few times before database seemed clean itself up.
There must have been some sort of hiccup in the final communication between the tablet and companion app when the backup finished. I can't seem to reproduce it though, so it will be difficult for me to diagnose what might be going on. Do you have a pretty reliable connection between the tablet and companion app?