Just jumping in here,

Running XOCE. Updated on the 21st June, never had backup issues but now all jobs fail as above. Don't have (and never have had) "Purge snapshot data when using CBT" enabled.

Rolled back to the update i did on the 4th June and all backups working as expected.

Thanks god for a decent rollback plan.

For those running XO from sources, you can "upgrade" again and select an older version. May get you out of the woods.