So the workaround is to remove the spanning tree protocol from lan bridge interface on microtik side? Tap interface in my case is bridged with a lan multiport bridge.

This is my Bridge Inteface attached

I have the same exact problem. 2 bridge clients connected (1 RV teltonika linux appliance and 1 macbook connected with viscosity). when the tap interface go up I correctly receive ad in from selecteed lan pool but no traffic at all. looking at arp records we can see all remote arp in incomplete stat...