This counter tracks CCMs whose logical-interface variant of the Interface Status TLV could not be validated, relevant on services where the interface being reported is not a physical port but a logical construct such as a sub-interface, LAG member, or pseudowire endpoint. Because logical interfaces do not map to hardware as directly as physical ports, this field is more failure-prone to encode correctly across different vendors' CFM stacks, making this a useful vendor-interop signal distinct from the physical-interface TLV counter. A count that rises specifically on services running over a LAG or virtual circuit, while physical-interface TLV errors stay flat, points at that logical-interface encoding as the specific weak link.