Mint comes back with a black screen after I turn off the VM

[Suwakoto]

Howdy ho. I have a Windows 10 QEMU/KVM virtual machine, that runs on PCI-Passthrough because I have only one graphics card. I have a script that unloads the drivers and anything graphics-related, unbinds the card from the host, and gives them for the VM to use, and then another script to do the same in reverse order when the VM is turned off. This setup worked well for over a year, however recently I updated my system from 20.3 to 21.1, and I noticed a peculiar problem.

I have two displays, which we'll call 1 and 2. I use only display 1 inside the VM, because I don't need any more. After I turn the VM off, display 1 comes back just fine, but display 2 remains black. The backlight is on, the monitor claims to be getting a signal from the computer. If I look both in the NVidia Control Panel, and the general Mint Display settings, both claim that the monitor is turned on and working, and windows can be opened there just fine. But the screen remains black. Turning it off and on (in the settings, that is) does not help, only thing I've found to fix the issue is restarting the system.

I was wondering if perhaps the issue is because display 2 is not used by the VM, so I tried enabling it there, only to have both displays return black after I turn the VM off. Even if I go into the VM and turn the 2nd display off, if it was used at any point, that's enough to have two black screens when I return to Mint.

It's not a deal breaker, since restarting takes 15 seconds. But it is nonetheless annoying. Does anyone have any idea how I could better understand what's going on and why, and how to fix it?