This read-only Counter tracks frames received by the CPU that were already flagged as errored before or during CPU processing. A rising count here, especially paired with ciscoTsStackSwitchLostFrames climbing too, suggests the switch's CPU path is under enough load or receiving enough malformed traffic that it's starting to struggle, distinct from physical-layer errors caught at the port level. This counter complements the per-port ciscoTsPortStatsPktsInErrors, but at the whole-switch CPU level rather than per port.