This has been an ongoing issue for our Surface Book 2's for the past few years. There isn't really one specific pattern I can pinpoint but here and there say if a user is working on their laptop, closes it up to bring to a meeting and goes to open it, sometimes the keyboard lights will still be on and active but nothing will display on the screen. No CTRL ALT DEL or anything will get the display back. We end up having to hold down the power button until Its fully powered off (you'll know once the keyboard lights go off) and turn back on. I've tested all different kind of power settings. Having all sleep and hibernation fully off (whether on battery or charging). I've yet to really find anyone having a solution to this.
UPDATE: To be more specific, it happens when the user is already undocked, and when they go back to their desk to re-dock is when it happens. When it docks and recognizes the external monitors, usually the laptop screen blanks out and back in when fully extends to the monitors but its when it blanks out and doesn't come back on, hence the machine still being actively powered on with the keyboard light active.. So one thing I noticed that has "helped" is if the user logs into the laptop first, THEN docks, it's less likely to happen. But when the user forgets that, it will still more frequently happen..