MS225 Switch Stack Mac Address Flapping

[UmutYasar]

Hi All,

I've configured and connected 4 x MS225 switches as a stack and enabled RSTP on the stack. But I'm getting mac address flaps for two macs as below. mac:A is flapping between SW1 & SW2 port2 and mac:B is flapping between SW1 & SW2 port1 as below. Port1 connected to MX1 and Port2 connected to MX2 .SW1 and SW2  port 1 and 2 are on STP blocking state, the 3rd switch's Port 1&2 are on forwarding state at the moment.

Why do you think this is happening?

Nov 26 10:19:37 MAC address flapping
mac: A, vlan: 1, port: SW1/2,SW2/2,Sw1/2
Nov 26 10:19:30 MAC address flapping
mac: B, vlan: 1, port: SW1/1, SW2/1,SW1/1

Topology is one edge SW, two MX connected to it as warm spare. And 4 switches stacked and connected to MX. One connection to each switch from each MX. The connection is the same as Meraki recommended in a full redundant switch stack for a warm spare for routed Hub on the below link.

https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair#:~:text....

.

[PhilipDAth]

Common causes:

• APs are connected to those ports and users are roaming between them.
• VMWare hosts are connected to those ports and VMWare is moving the VMs between the ports.

[UmutYasar]

@PhilipDAth , Actually these ports are connected to Primary and Standby MXs.But MXs connected to a LAN switch, and there is APs working on the same VLAN. These may the macs of the users on these APs. I'll try to find the mac owners.