[Delgado]

For whatever this comment may be worth at such a late stage in the posts, I have found K5s to be a bit over-sensitive to colour temperature shifts simply through slight change of camera position. This is noticable in comparison with the K7.

Generally my solution is to either set a custom white balance using a Whibal (white balance reference card) or, more simply, include a picture of the Whibal one or more shots and use that as a white balance reference when I import the files into Adobe Camera Raw. The custom white balance would probably suit jpeg shooters better. I always use DNG.

[kittykat46]

Yes, I've been able to recreate the same problem under fluorescent lights at higher shutter speeds
The K-5 is the pretty much the first camera I've had which can be used for no-flash shots indoors at high shutter speeds, thanks to its excellent high-ISO capability.
This is an unusual case where one of the K-5's significant strengths causes an unintended photography problem under special conditions.

[WerTicus]

strobist blog says this is normal at faster than 1/60th