LR3 import changing WB

I have just started with a small home studio and have a simple setup (One AB400, 60x30 softbox) to take photos of our new baby. I have multiple backdrops and have used some very light colored ones until recently. I just used a violet colored cloth backdrop and while taking the photos the colors were true on the viewfinder.

When LR3 reads my CF card I noticed the colors were the same as I saw on my viewfinder. However, once they are copied into the Library, LR3 started changing the WB on me. Instead of seeing violet, the backdrop changed to purple. I actually watched it as LR3 changed each photo one by one. I put the CF back in my camera and sure enough it showed violet. What I thought was very weird was the fact that the colors were violet when LR3 was accessing my CF card but once in was in the Library LR3 changed my WB.

Under Quick Develop in LR3, I changed my WB from At Shot to Flash and sure enough the violet color reappeared. This is how I had my camera setup:

5DMII
Evaluative Meter
Auto WB (when I switched WB to Flash I noticed no difference on the viewfinder)
SS: 200
ISO: 100
AV: varied

So essentially I am wondering why LR3 is changing the WB on me from what it sees on the CF card. I have never noticed this happening before but I mostly shoot outdoors with Auto WB and this is my first experience shooting indoors with a strobe.

Any thoughts/suggestions would be appreciated.

It's applying the default preset when rendering the raw data, instead of showing the jpeg the camera embedded. The preset may have auto white balance turned out. Work out what the default preset is and change it to use the WB the camera told it to.

Have you double checked that it isn't set up to apply a preset at import? What does the color temp and tint show for as shot and what does it show for flash??

PS - Do yourself a favor and don't use auto wb with controlled (and consistent) lighting. Your wb will wander and you will have to adjust each one individually for a truly constant result. Actually, it will wander under the flash preset for some reason too. IMO, for what you are doing you should really use a grey card or other calibrated target with a custom white balance set in camera.

What you saw on the camera's lcd was, of course, the product of the camera's processing which creates a jpg and embeds it into the Raw file for that purpose (because a Raw cannot be directly displayed.) Like many other programs LR utilizes that jpg for its display of thumbnails and loupe views in the import dialog, then when the imported image is displayed in the Library module the display is replaced by the initial LR conversion, processed according to LR's defaults. If the default WB is As Shot, LR reads the values of the WB adjustment used by the camera for the embedded jpg and listed in the file metadata. However, the use of the same numerical shifts does not always have the same effect as it did in the camera because LR is starting from a different starting point, i.e. from a different profile. When you set the Flash WB preset LR used its own values that the Adobe designers had calculated to produce good flash WB when used with Adobe profiles.

Thank you for the responses. It is much clearer now, I forgot about the jpeg and RAW difference in my viewfinder and what LR is using. I am a complete newbie with shooting in a studio setting and just started using LR as well. I never noticed the shift in WB before but it makes sense now. I appreciate the input!