Backup is not created if no modules are selected

If I don't choose to backup any modules and include only a custom directory the backup fails. FreePBX reports that the backup succeed but the tar.gz file is not generated. If I include just one module the backup file is generated with my custom directory inside it. The version of the module is 15.0.10.68. FreePBX version is 15.0.17.64, I filled 15.0.17.55 because Jira didn't allow it.

My directory has the following rights

[root@freepbx monitor]# pwd
/var/spool/asterisk/monitor
[root@freepbx monitor]# ls -lh
total 0
drwxr-xr-x 2 asterisk asterisk 39 Dec 20 13:15 temp

Same problem occures even if I add a second directory so I guess it doesn't matter how may I have added the backup is not even initiated.