A&H,
Observed on 1.7x and 1.80.
System operating, disconnect surface. After about 15-20 seconds you receive the lost communication notification and can “Restart” or “Shut Down”. You have about 30 seconds to respond to that, if you wait then the surface freezes and won’t take any input. Hard power down & recover.
It may sound odd, but one of the environments I run in we do this all the time in competitions. Setup, Warm up, disconnect, roll to contest location (everything on UPS), connect, perform, disconnect, exit field, gracefully power everything down.
A cold boot on a surface is about 1:45, a warm restart is about 1:00.
Jay