I upgraded to the AU to test this out, and I've been investigating this -- again this issue is definitely not obs' fault at this point, especially after seeing it first hand. I believe it's some sort of driver or internal windows race condition when multiple 3D programs are active at once and when VRAM is near exhaustion, which is why it probably has taken so long for them to do anything about it. It happens only under specific conditions.
The conditions to make it occur *seem* to be that multiple 3D applications (particularly OBS and D3D11+ games) need to be active while VRAM is near exhaustion, then some sort of race condition is happening when the card has to fallback and use system RAM for video resources. OBS can typically use up to 200-300 megs of VRAM so it's understandable that it happens on occasion. Especially seems to happen with OBS and Direct3D 11+ games, games that are prone to eat up all the VRAM when used in conjunction with OBS. Something in that process there can trigger some sort of race condition to occur in the driver or internally in windows, and the driver just freezes up and has to be terminated, causing obs and all other 3D programs to stop rendering or outright crash (with D3D11 returning a device hang error). Another reason I suspect a race condition is because it doesn't seem to really happen when the game or obs is running by themselves, though I can only speculate unfortunately. I can't say for 100% sure what's going on because it happens in driver modules, but that's my best educated guess.
Predominantly seems to happen with nvidia cards with 4 or less gigabytes of VRAM, though we've had some reports of AMD cards having total driver restarts as well, but they've been much less frequent than nvidia, so I don't know if AMD issues are unrelated or not. Almost never happens on the more recent series of cards with 8+ gigs of VRAM.
Reproducing tends to be sporadic, but some users have noted that it happens all the time with specific games for them. For one person, they used OBS studio with a geforce 980 and capture forza (via display capture), and for that particular individual the issue seems to happen every time.
I'm sure they're aware that something strange is going on. If it's a race condition that only happens under very specific circumstances, then it's far harder to catch, debug, and track down, so it would explain why the issue has gone unsolved for longer than expected by microsoft or nvidia. Most of the time users are not running multiple 3D rendering applications at once either. Streaming is sort of a special case.
So that's my preliminary investigation and thoughts on the matter.
At this point I just need to get in contact with driver engineers at nvidia, or engineers at microsoft somehow. I pray to god I can actually get in contact with someone.
Again, this is not a bug with OBS. It's mostly just an unusual circumstance that they haven't caught in testing yet.