Rhino 8 section issues

Hi, I’m having a few issues with Sections not really showing geometry correctly.
You can see in the attached screenshot, I have a keelson (left) with lighning hole that is showing incorrectly. I thought it might not be registering the lightning hole properly so I untrimmed it (as per right side), but you can see that it’s still not showing correctly.

Geometry wise it’s a piece of 8mm extrusion with the section running down the centre line. The geometry is set to show section style by clipping plane, which has the settings in the screenshot.

Any ideas on what’s going wrong here?