Distortion while panning with Optura 400

I purchased my Optura 400 a few weeks ago. I have not used it outdoors yet, but I noticed something odd when panning indoors. While I pan left or right, the picture gets distorted and looks like the choppy videos that can be taken with some digital camera's (as though there aren't enough frames per second). The choppiness disappears as soon as I stop panning, but is this normal? It doesn't appear to be normal to me. I'm trying to monitor exactly when it happens and it appears that it may occur more often when there is not a lot bright light. Any comments/suggestions?

Here are two links to other past threads that seem to be addressing a similar problem with the Optura 300.

http://www.camcorderinfo.com/bbs/t75137.html

http://www.camcorderinfo.com/bbs/t68198.html

Quote from the first link:
"This cam can give fantastic results on a sunny day both in resolution and image stabilization but things seem to go badly wrong when the light drops. the problem seems to be that Canon has tweked the auto mode to such a point that in anything but perfect light the cam wants to go towards the low light mode slowing the shutter with the result that you can shot 2 scenes in a row and they do not look as if they are taken on the same camera! I think this combined with the electronic stabilizer may be the effect you do not like. "

Chrystie