For what it's worth, we're having the same issue. So far the response I've gotten through ticket is that it is not supported. Which strikes me as odd, because if you do a clone job with all the same resources as the backup; it will run an on demand backup, and then mount it. So it essentially seems to do what they say is not supported.
Our attempt at a work around Is to run the clone, and then script out the recovery of the other databases. We're attempting to remove having to do the clone from SnapCenter 3.0 and just control it all from the script. Unfortunately, I've yet to be able to figure out the new-SmClone powershell cmdlet. Even with an open support case for almost two weeks now.