Originally posted by derekkite 
What it's your C2 11 set to?
That setting is only applicable when using the on board flash or a P-TTL flash. When using a 'dumb' flash the camera will not actually know that you are using a flash and will ignore that setting.
In general whenever using a 'dumb' flash the white balance should be set manually to the 'Flash' setting unless you are deliberately trying to achieve some special lighting effect. That is general good practice with any camera system, not just the K-3 or even Pentax.
For AWB to make sense in a flash exposure the camera needs to know what the image looks like in natural light
and what it will look light under the strobe light. Otherwise the areas not illuminated by the flash will likely mess up the AWB algorithm to a greater or lesser extent, even if applying it to the captured image (as almost all cameras do).
The K-3 instead seems to always use the RGB sensor. While this is normally a good thing, especially for flash exposures (with P-TTL), the way they implemented it will unfortunately be very likley to be 'tricked' by a dumb flash because the actual picture it shoots will be very different from what it expected based on the RGB sensor, In my opinion this is somewhat flawed logic in the design but very easy to fix (for them) and also of very little consequence since the Flash preset WB should be used anyway in such situations. In other words it just makes the photographer's mistake worse but if the photographer does the right thing then the camera will perform perfectly.
Something to fix for sure but I wouldn't even think of calling this a major concern.
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