Animation.Sample not updating animation transforms?

I'm trying to cache out the frames of a model's animation to a sprite atlas. This is being done in a disabled/offscreen camera. I can set the time once and it will immediately update (regardless of whether I call Animation.Sample() or not). If I do it a second time during the same frame, it will fail to update the position. Once again, calling Animation.Sample does absolutely nothing.

Am I missing something here? It seems like Animation.Sample is what I need, but it doesn't seem to affect anything. Also, why is it updating the animation the first time I set AnimationState.time (without calling Sample)? All of this happens before the animation update stage...

Hm...sounds weird. I can't remember seeing any problems like this with Animation.Sample. Can you post your mini-project somewhere?