One thing we recently learned about the command created in Ola's output file cleanup job is that if you are using a UNC path for your backups and/or Agent Job log files then the CmdExe script will not work as UNC paths are not supported.

In our case and as a temporary solution, since we have a 3 node cluster using SQL 2014 Availability Groups where only the backup volumes are leveraging the same shared storage volumes for our backups, we opted for just altering the Output File Cleanup jobs to use the physical drive letters since these shared volumes are usually hosted on the same node. Of course I the event of a failover we would have to make a manual adjustment but that is a better option than not cleaning up the Agent job files at all.