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 the current, still-open 15-minute interval -- a value that keeps climbing until the interval closes and rolls into history. For example, so far in the current, still-running 15-minute interval, this pseudowire might show this counter at 2 -- a concrete count the admin can trend against neighboring bins to judge whether the condition it reflects is worsening.