Problem with D800 Manual White Balance

Wondering if anyone else is having this same problem.

I have a D800. I was initially able to set the WB to PRE and then hold the WB button down for a few seconds to get the "Pre" to flash and take the WB measurement. However, today I was trying to take new WB measurement.

No matter how long I hold the WB button down, I cannot get it into measurement mode witht he "pre" flashing to take the measurement.

I have done it before a couple of days ago without issue, now I can't get it to work.

Don't know if this is a firmware issue or if others are experiencing the same.

The WB button still works, I can change all the settings, its just that holding it down will not get it to go into measurement mode where the "pre" blinks for you to take a measurement picture.

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I am not a brand loyalist, I can take equally bad pictures with any brand...