"createTarFork() process ended with ERROR: 255"
"Backup failed. Cleaning Backup Folder."
I do not have multiple users set up (TWRP is known to have problems with that).
Recovery Log (only latter part due to file-size):
In the log I found this notable part:
failed to lookup fscrypt tar policy for '/data/extm' - '600abdeb88d2da0f8f374d53b133c57b' I:Error adding file...