Multicast Session Reset on Rejoin event

I successfully make some development on your Fuota Server and I am able to use Multicast feature well. My devices are OTAA Class C. Devices running on both a Unicast session and a Multicast session at the same time. My question is:
Am I forced to reset multicast session parameters(mckey, mcaddr, mcFcnt…) after unicast session REJOIN event ?

I think they are independent from each other. I can store multicast session parameters and use them after the device Rejoined the network. So I dont need to re-setup the multicast session.