This counts packets that failed VC-level processing for this pseudowire, with the MIB explicitly citing packets arriving with an unrecognized VC label as one example cause. A nonzero and climbing value here, even while cpwVcOperStatus still reports up, points to a label mismatch or stale label table entry somewhere in the PSN that's silently dropping a fraction of the VC's traffic rather than taking the whole circuit down. Seeing this counter increase in lockstep with a customer's report of intermittent packet loss narrows the root cause to VC-level label handling rather than a physical link problem.