Per the MIB, this counter increments when a received frame is dropped because CFM processing mode was administratively disabled at the time, while the object's own name, referencing an invalid Etype, points at Ethertype-based frame filtering as the check involved. This matters because it flags CFM frames still arriving on the wire after an admin has turned fault-management processing off for a segment, meaning a remote peer has not yet caught up with that local configuration change. Seeing this counter keep climbing well after CFM was disabled on this device is a sign a remote peer is still actively probing this MEP and needs its own configuration updated too.