For what it's worth, I saw almost the same thing. We have done several tests with the AIM data unit and sensors in both the intake pre-afm and then in the plastic snorkel right up against the throttle body.
On a 90 degree day with Springfield Dyno radiators running water temp in the 170 range I saw a 27 ish degree swing from pre-afm to pre-throttle body.
Turn Signa In - Pre AFM = 132.9, Pre Throttle Body = 135.8
Turn Signal Out - Pre AFM = 90.1 Pre Throttle Body = 117.8
I completely agree with the science above in Jason's post and the fact that it does not seem possible to increase the temperature that much, but I have now seen it on two different cars in two different scenario's.
The only thing I can think of is that the throttle body has a water jacket that is fed from the cooling system to ( I think ) keep the throttle bodies from freezing up in the winter, so is it possible that the combination of the under hood temps, air passing through the radiator hitting the snorkel and then the heating of the throttle body through the water jacket be causing the increase in temperatures? I assume that whole intake manifold (after the throttle body) has to be right up there with the water temp.
Sean