This counts occurrences of the CESoP-specific M-bit being set in the control word of packets on this pseudowire, used to signal additional defect/mode conditions beyond the basic L/R bits. Because the M-bit carries CESoP profile-specific signaling for this pseudowire, a rising count here alongside otherwise normal traffic usually means an interoperability or mode-mismatch condition with the remote endpoint worth checking against the peer's configuration -- and this specific object covers a cumulative counter reset only by an explicit clear rather than on a fixed schedule -- reflecting everything since PM stats were last cleared. For example, since PM counters were last cleared, this pseudowire might show this counter at 20 -- a concrete count the admin can trend against neighboring bins to judge whether the condition it reflects is worsening.