Slice "Wall" blocking cross section

 Hey team. I've got something weird showing up when I cut a slice.

There is a shadow "wall" or something blocking the cross section view. I have a few different borehole data sets in the model, and the wall only shows up when a certain borehole geology or collar is turned on.

Anyone seen something like this? Is there something in the borehole data that would make it display like this?