This counter tracks aligned frames that were discarded specifically due to CRC errors. Because these frames were correctly aligned, ruling out a timing/framing issue, but still failed the CRC check, this points to bit-level corruption on the Ethernet cable itself -- a bad connector, cable, or EMI source -- rather than a duplex or switch configuration problem. If this counter climbs specifically after a new piece of equipment, like a nearby motor or unshielded cable run, is installed near the Ethernet cabling, that timing correlation would point investigators toward electrical interference as the cause.