i think i found what the problem is. The MS dock power supply simply does not provide enough power (90 W), it produces even less than the original Surface Book 2 power suppy (95 W for the Surface, 102 W including the USB).
To resolve the issue right now you have 3 practical options:
- do not use your Surface Book 2, connected to the Surface Dock, in "best performance", but rather find the performance-power equilibrium that best adapt to your particular situation; i would begin by "best battery life" and try for some time and increase it a bit until it start to disconnect intermittently again.
- Get the new Surface Dock 2. It's being announced with a 199 W power supply.
- Get a more powerful power supply that fits in the dock.
as you read above there is no software update, configuration (other than power consumption), replacement, or other that will let you enjoy your dock and Surface Book together to the fullest