Counts received frames whose length field states a value within the valid LLC data size range but that doesn't actually match the number of LLC data octets received, or states a value smaller than the minimum allowed. A nonzero count flags frames with a mismatched or malformed length field, which can indicate a misbehaving NIC, a corrupted frame, or non-standard framing on the segment. For example, a frame claiming a 46-byte payload but actually carrying 40 bytes would increment this counter on the receiving interface.