I know with the CUDA errors, once the error occurs, all subsequent renders will also fail. But closing Poser and restarting it will reset that. So you could have scenes/frames that render just fine with Optix, but when you try to render them after an error it appears they don't work, because the original error has not been reset yet. The majority of what I'm doing (typically cycles, superfly) works just fine with Optix, a smaller proportion of scenes will fail typically only for a few angles and need to be rendered without Optix.