When mgmt port goes down, vlanmgr sends a message to clients on the link down.
<Info:vlan.msgs.portLinkStateDown> Slot-1: Port Mgmt-1 link down
<Data:vlan.msgs.portLinkState> Slot-1: Tx Msg: Sending link state of a port: slot: 1, port: 0, state: 0
The message contains slot and port as slot=1 port=0.
But after mcmgr receives this message, the port value is changed from 0 to 1 and this is further passed down up to the function, where a delete of the cache entry is performed for slot 1 port 1 causing this issue.
<Data:IPMC.VLAN.DelPortHal> Slot-1: Invoking HAL_IPv4_MC_DELETE_PORT src=10.1.1.1, grp=188.8.131.52, inVlan=v1, port_vlan=v1, slot=1, port=1
The issue does not happen on a standalone switch
Disable and enable port 1:1 or bring up mgmt port.