When the fast leave feature is enabled and the last host leaves a multicast group, the router immediately removes the port from the multicast group. The router does not query the port for other members of the multicast group before removing the group, and/or the port.
The default setting for IGMP (Internet Group Management Protocol) snooping fast leave is disabled.
enable igmp snooping {vlan} name fast-leave
disable igmp snooping {vlan} name fast-leave