I'm trying to cut this in half using the front plane but it is not working whether using cut with surface or a simple extruded cut. This is affecting the assembly that it is going to be on, which other parts, except this, have no issues being cut in half! I can't even use the section view on the darned thing which I don't want to do but just noticed.

1. Extruded cut

2. Cut with surface

What can I do?