I am having the same problem. I think it is connected to the fact that Explorer sometimes cannot find my desktop. I have been an MS and surface loyalist, but I am about to dump it all.
I strongly support changing to a TB3 dock connection, so that we could use a GPU in the dock (ala Razer Blade Core).
Both for the SP line and for the SB line, I think this will allow a much more natural portable v desktop setup.