Hi Guys,

i had a fresh install of two CRS354-48G-4S+2Q+RM cross connected via 2x 10G LACP LAG.

I did 4 vlan port-groups:
1-12 VLAN 10, 13-24 VLAN 20, 25-36 VLAN 30, 37-48 VLAN40

One switch stopped working on VLAN20, all ports on VLAN20 (13-24) were "deactivated". It was not possible to find the device via WinBox-Discovery and all devices attached to that portgroup were not able to see each other.

Deactivating all Ports and re-enable all ports did not fix the issue.
Also changing VLAN PVID to 21 and back to 20 did not fix the issue.

Only a power-reset was able to fix the issue.

We have firewall 1 connected to switch 1 and firewall 2 to switch 2. The firewalls do a heartbeat and in case one box is unavailable it do an switch and set up the same mac-address on the other device. So i thought that it could be an ARP SPOOFING related issue? But i can not find any related configuration in WinBox / CLI. to enable / disable arp-spoofing features.

Was the device failing without any reason?
Or have the device some security options that may encounter that behavior?

Network-Setup: