Exactly as described, this counts received packets longer than 1518 octets that also carried a bad FCS or non-integral-octet alignment error -- corrupted oversized frames, distinct from the clean oversize counter above. A jabber traditionally points to a transmitting NIC or port stuck sending an overlong, corrupted frame, so seeing this climb on a reflector port during a test suggests the remote generator's own transmit path, or something upstream of it, is malfunctioning rather than the reflector itself. For example, jabber counts appearing only when a specific remote test set is used as the generator, and not with others, would point suspicion at that particular piece of far-end test equipment.