I've seen the samething a couple of times in GWX but both were not Large Merchants. The second contact can be lost even if it's a little bit behind the first contact.
Have ypu seen this yet? It's actually a bit funny to watch. A wolfpack hit them the same time as I did and put the merchants in chaos.
They had no idea where to turn to and several ran into each other becoming stuck together, tho each had to be sunk seprately. These did turn and were alll over the place. Sometimes going in circles.
