The joys of parts with not friendly printing geometry. There’s another cylindrical recess running at 90 degrees to the one that’s visible in this photo.
Apologies for the very obvious layer lines. Harsh direct overhead lighting makes them a lot more obvious. The prints are much better in person, I promise.
Edit: Finished part showing the second cylindrical recess. They’re both dimensionally important, which is why the parts weren’t printed flat.
I updated the OP. The dimensions in the arch is the feature that matters for this print.
The prints really do look pretty good under normal lighting. The orientation did not impact print quality. Elis has a nice demo of this on his site