I have 3 sites in a standalone multisite setup and recently noticed that only one of them is actually performing the scheduled backup.
There does not appear to be anything in the logs about the other sites failing to backup. The
unicorn.stdout.log shows only the one site being backed up. A manual backup of all sites works fine.
It seems to have stopped working around the time I updated from 1.4 to 1.5 (on 1.6 now but no change).
Any ideas on how to diagnose this?