Calculations that work in After Effects but not in Premiere Pro

I'm developing another Premiere Pro plugin based on AE effects SDK.

The plugin manipulates pixels in a very simple way - based on lift/gamma/gain controls it changes the values as such:

colorRGB->blue = PF_POW( colorRGB->blue , gamma) * gain + lift

And so on for the red, and green. All in floating point, PF_FpShort. I even tried doing calculations in PF_FpLong, but the results were the same.

Later the values can be clipped using MAX and MIN macros.

In After Effects everything works perfectly. In Premiere Pro, once certain gamma treshold (less than about 0.5, more than about 1.4) is reached, I start getting weird artifacts. Either green pixels or black squares in random patterns, usually, but not always, corresponding to the darker parts of the image.

I have no idea why, and how to correct it.

Please help.

EDIT: Actually any gamma that is different than 1 results in these weird artifacts, and only in the BGRA_32f mode. BGRA_8u works fine.