I read the post you linked, and saw the pictures. I didn't see the film though, because I'm at work. It seems similiar to the D9. To me the D9 seems to have a random snap roll. Well, it's not really random. It's more of as you start pulling G. However, it seems to snap roll at any speed. I've done it from 450 knts and I try to pull out of a dive OTD, pulling about 5-6G. I've also done it at 2G while doing 150 knts in a turnfight situation.
Did you read Tango's analysis in that post of what he thinks happened? It's not really a snap roll per se, it's an adverse yaw problem common to high-aspect ratio wings (basically a higher yawing moment due to asymmetric wing drag. Looks like Lusche was trying his hand at drifting.

I've experienced the snap roll problem you're talking about in the D9, and yeah, it seems to happen at any speed.
What were you doing turn-fighting at 150 kts in a Dora? Even the CV's have better turn performance.