Iv'e had something like this happen once to me, My totem is in 937 where the Cenderrat spawn point is/was, i equipped my cart and then traveled over to 936.
I unequipped my cart, cut down a tree and then chopped it into logs, cut them into blocks and put them in the cart.
i was able to open the bins and access the inventory inside the cart, but the Use option was gone, i logged off then back on and my cart was gone.
i searched and was unable to find my cart, eventually i returned to my camp and my cart was there with the wood i put in it.
There was no indication that it wasn't attached to my character, in fact i was encumbered by the weight of the cart while moving, travel across water was blocked by the dept of the stream.
not to mention the cart was visible on my client the entire time, including clipping the player.
I was using the steam client, i did not think to load up a second account and login with the xsyon client but if it happens again ill go do that.
all actions fired off with no signs of latency either.