Windows 10 Version 1803 resolves this problem for me. I've been running full screen 4K web meetings without a single screen blackout. I plugged the Mini-Display Port back into the dock vs the surface and it also works.
Perhaps someone could also verify and mark this as resolved.
I am still getting flickering on the external monitor with version 1803.
Is your symptom exactly as shown in the youtube video on post number 1. My understanding flickering is a different issue.
Yes, my issue is the same as shown in the OP. Here's my set up with external flicker (on/off):