Inconsistent Dimensionl Inaccuracy

Hi, I have a form 3, and have been having trouble with dimensional accuracy in an unusual way.

Specifically with holes being 120um smaller than they should be. At first i thought it might be an issue with walls being thicker than they should be, but it is not. I printed the testform and the rectangle holes are all 120um under size in the width, their walls are all 1mm as the design says, so no sagging. The fins are correct thickness. Any help would be great