Using a circular polarizer with EX1

I'm just about to purchase my EX1, which I will use almost exclusively for nature footage, which means I will be using a polarizer filter (and GND filters) quite a bit. I was reading on another forum where someone was having issues with color shifting when using a circular polarizer with the EX1 while panning. He had tried three different polarizers to make sure it wasn't a problem with one specific brand. I haven't read of this problem elsewhere, but I don't know if many people are shooting wilderness stuff with a polarizer. It's of serious concern for me due to the 'nature' of my shooting style.

Is anyone here using a circular polarizer and are you having any color shifting (magenta/cyan) problems when panning? I'm a photographer so I know about polarizers and the effect of the sun angles, etc., but color shifting? Hmmmm.