This Counter32 counts received VSL packets that did NOT indicate a bidirectional link, i.e., signs the connection may only be working in one direction. A growing count here, especially alongside a stalled cvsVSLPortRxBidirPkts counter, points to a partial VSL failure that could risk a dual-active split-brain condition between chassis. An admin monitoring virtual switch health would treat a sudden spike in this counter as an early warning to inspect the physical VSL cabling or optics.