This counter increments specifically when a CFM frame queued for flooding carries a destination MAC that does not match the multicast address 802.1ag/Y.1731 reserves for that frame's Maintenance Domain level, so the device refuses to flood it. Since each MD level (customer, provider, operator) has its own dedicated multicast MAC, this is a concrete way to catch a misconfigured or corrupted CFM frame, possibly from a third-party device with its level-to-MAC mapping out of sync, before it gets flooded where it should not go. A nonzero count here with no matching rise in the flooded-frames counter tells an admin some device on the segment is generating CFM frames with the wrong level-to-MAC pairing.