This counts received PW packets whose header or payload size didn't match what the CESoP encapsulation expected, so they could not be interpreted as valid TDM payload. Malformed packets on this pseudowire point to an interoperability or MTU/fragmentation mismatch with the far-end PW endpoint rather than ordinary network loss, since a healthy peer running compatible CESoP settings should never emit them -- 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 15 -- a concrete count the admin can trend against neighboring bins to judge whether the condition it reflects is worsening.