I'm really not sure what could have happened there. As far as I'm aware there's nothing in this upgrade that would cause this - it almost sounds as though some of the machines' properties were changed, which the upgrade doesn't do.
I'm really at a loss here, I'm afraid
What DAT version is being reported by the machines that are showing as non-compliant?
Just to update and close this one out. It took about a week but things came back down to normal levels of non compliant machines. My guess is that something got changed in the ePO database. Then when the machines sent in updated properties it got updated.
If i recall correctly the incorrect version being reported was from 3 to 6 months ago. I could make no sense of the DAT being incorrectly reported. Nor could I see a pattern to it.