Ruckus has a directed-multicast feature that will by default, convert the first 5 multicast (UDP) clients into Unicast (TCP) for better delivery.
This is usually optimal for many applications, but not all. In your case, you probably want to let all multicast join/updates to flow unchanged.
KBA-4568 might be the most helpful to determine which WLAN you're using these clients on, and how to disable directed-multicast and
either enable or disable IGMP snooping (try disabled first, meaning let the pkts go clear to the client, don't have AP answer on their behalf).https://support.ruckuswireless.com/answers/000004568
[ this article may not appear until the next Support site 6hr update period, as I just opened the visibility to public. ]