Today, I disconnected the screen from the keyboard. But once that was done, I wasn't able to open any apps. The screen was unresponsive for at least a few minutes. Then it worked OK.
I would not say that is normal but I feel that the behavior of the tablet when detaching and attaching is still a bit random. I experience some minor glitches now and then. I still don't feel confident that it will work when i detach the tablet on my device (I'm talking Surface Book first gen)
Had you been running any heavy applications before you detached the tablet? Some app that used the dedicated graphics card a lot and was not shut down completlyt before you detached the tablet?