Bluish flashes

There is a problem with blue marks on the Sony 707 but I've never heard of any problem on the Fuji.

Does the flash coincide with handling the camera. If you tap the camera does the blue flash happen or is it completely random?

If it coincides with physical shock then I'd say you have a bad connection on the video board. Either a dry joint or loose ribbon cable.

If it's completely random then it sounds like a real tough fault.

I've checked if there's a firmware upgrade but noneare available.

Are you sure it's not reflections caused by lighting or the sun hitting the lens at certain angles.

So we can rule out the LCD because it shows up on the picture taken. We can rule out lens addons due to it being intermittent. All I can advise is an email to Fuji support explaining the problem fully and maybe a few pictures showing the fault. If it's a CCD or videoboard problem it will mean a trip for the camera to a Fuji repair agent.

BMW

It could be usefull to have an attachment so we could see how it looks when it occurs. Have you tried working with the manual white balance?