Strange "resin accuracy" problem

Hi, folks. I have a Form 3+, and have observed a recurring problem that may already have a name. The finished print looks like there was resin sitting atop horizontal surfaces and cured there. I know that is not the explanation, and I do have a hypothesis.

If you look at the picture, you’ll see the effect at the top of the major diameter of the part. You can also see it on the bottom of the holes. (This part was 15-degrees off vertical.) Note that the major diameter looks perfect at the 3-o’clock position where it is vertical, and worst at the 12-o’clock position where it is horizontal.

It is NOT excess resin on the part before the cure station. I have a FOUR stage IPA cleaning process.

Is is possible that the resin above a very thin layer is getting cured THOUGH the layer? Does this effect have a name?

This resin is Grey V4, but the effect was also observed on Tough 1500.