D800 Orange Burn: Little Help, Please?

All recent Nikon dSLRs have a strong anti-IR filter in front of the sensor. See for instance this link which comments on the D90:

"The D90 and the more recent Nikons (as well as Canons) are among the worst  offenders because of their strict infrared-blocking filters."

That's why it is highly unlikely that "IR pollution" is the problem here. The response to IR is just too weak.

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Thierry - posted as regular forum member