I had the same failure on Friday. 100% full SSD. Michael checked several things, and we decided corupted SSD/file system is the likely cause, so restoring SDD from an image was the best course of action.
Here the process, though I'd wait until support contacts you, just incase they want to see if they can find the source of the missing disk space:
https://forum.universal-devices.com/topic/42174-polisy-ssd-image-restore-process-for-a-corrupt-ssd/
My eisy arrives tomorrow, so I'm glad to hear the restore from polisy backup to eisy should be smooth and painless...