I did another quick check while leaving the Vive on. Out of everything I have done, this is the ONLY consistent factor in this issue. Reinstalling a fresh copy of Windows 10 admittedly DID add a minute or so before the grey space started to take over, but unplugging the second monitor just 100% fixes everything on the spot. Unfortunately, my motherboard doesn't have an onboard video card, so that isn't an option. If there is no solution to that problem, then honestly, I'm okay with that. Playing in VR is incredibly fun and if I have to move a few windows to their correct monitors afterward every time, then I am completely okay with this.