I'm experiencing a similar issue.
Using Windows 10 and CMO, if I pause the game, lock my computer (Windows Key + L ) and then come back a few minutes later there is a big red cross over the map window. I believe this might be down to a low memory issue?
At the risk of conflating issues I do they they are very much related in the sense I think in both cases there may be a display resolution or video-driver reset\re-init taking place and the game's display\video-card related references it previous had become invalidated (pure speculation) in whole or in part (the map display) and it can't recover (or doesn't attempt to). I base that speculation only on that I can make this same thing happen on demand by manually restarting my video driver with the game open. Which not super surprisingly produces the issue (not complaining). What is a little surprising is the number of apps that actually do not get affected or recover without issue, I presume because they either trap for and can handle the event(s) or just aren't as directly talking to the driver\hardware.
As for it happening with "just locking", I can reproduce it on win7, one needs only to load a scene or the editor and ctrl-alt-del and lock, then wait a few seconds and go ahead and unlock. The map display will not recover from the red-x condition, even though most of the time the app itself will (sort of) recover enough to file|exit, though often it may just crash. I have a one monitor, one pc setup, amd card|drivers. This does not occur when the monitor just goes to screen saver or into power save mode (at least not in my case), it takes the locking action or a driver reset.
As mentioned above if anyone needs to know how to repo the driver reset specifically like for what may be going on with the kvm and testing, you can also trigger it via:
Win+Ctrl+Shift+B on win10
CRU utility(restart\restart64) for amd\nvidia, devcon (windows sdk\ddk), or super manually via device manager disable\enable on win7\8.