This counts loopback replies that arrived without a matching outstanding LBM from this device to correlate them to, essentially replies this device did not ask for, or that arrived so late their original request had already timed out and been discarded. A nonzero count here can indicate stale replies from a previous loopback test still trickling in, or in less benign cases a misdirected or spoofed reply on the segment. Seeing this counter increment well after an admin's loopback session ended is most often just late-arriving stragglers from that same test rather than anything malicious.