Okay guys tough one for you. This may be an unfixed bug of Poser4. (BTW I'm using the latest patch from Curious Labs and this also appears in the prior Ghost Effects patches) Import a behavioral file like the ones included with the P4 Content CD, go for one that has movement and jumping. Now try to expand the # of frames by adding frames in the Animation Controls then going to Animation>Retime Animation (while making sure that the figure is selected). When the character jumps or leaps into the air it will spin mysteriously in thin air during several of the animation non-key frame segments. Apparently the hips are rotated on multiple axis. This will also happen if you Import a behavioral file, then resample key frames. Let's say for the Current Figure and every 4 frames for the full duration. Again on the non-key frames the character will spin. And I have been unable to remove the effects of the non-key frames, can't delete them, and it does nothing to make them key frames then delete them. So far I haven't noticed a method of removing these malicious frames. I have done several checks with this, so far it doesn't seem to be due to the # of frames in an animation. I have done it with as many as 1736 frames or as little as 30. It doesn't matter what kind of figure you use. For my testing purposes I've been using the P4 Lo figures. I have also tried Spline Section and Linear Section for the problem frames with no improvement. Please let me know if anyone else has experienced the same thing, and perhaps if a cure has been found.

Have you tried playing with the quaternion switch. That can help. Also setting the interpolation curve to linear may also help.

Already tried that.