I've found a bug in the SG200-08P switch (probably firmware; latest is installed). Is there a way to report this without a support contract?
The bug is that frames with MAC destination 01:80:c2:00:88:bf seem not to be forwarded (should be flooded). I guess because 01:80:C2:00:00:00 to 01:80:C2:00:00:0F is a reserved range (IEEE802.1D-2004,7.12.6) and perhaps just the first three bytes are being matched and the frame dropped.
That MAC address is used by MikroTik devices and not forwarding it breaks their RoMON functionality.
My SG300 switches do forward those frames, as do the other switches I have here, but as soon as I put the SG200 in there, it fails. Apparently some Ubiquity switches also do not forward it and that has been acknowledged by Ubiquity.