Hi there
I have the exact same issue.
Screens is flicking when using external screens - connected via dock as well as connected directly to the book via miniDP.
I have tried:
Reinstall windows 10
Other monitors - Philips, Dell, ASUS, HP monitors.
New cables
Other adapters (miniDP to DP)
New firmware
New drivers
Talked to Microsoft support witch agreed to exchange the product, but after 3 week I got the same book back with the note that they have found a scratch, so they would not do the exchange anyway. (this problem has existed always, from the product was brand new, so it have nothing to do with that scratch)
PLEASE help, this is annoying as hell.
Kind regards
Christian - the frustrated IT guy