Raster render produces non-existent lines

Layout drawing is displaying some non-existent lines when rendered in raster. See the comparison photos below around the valves. These lines also appear when using hybrid. I thought raster was supposed to be less sharp / faster than vector, not actually change the look of the model image. Can anybody provide clarification?

Vector image is clean

Raster & Hybrid gives these bogus lines

I did a little more investigation. I found the same lines appearing (though much smaller) in a larger scale isometric view.

Turns out that the valves, which were modeled by their manufacturer in some other software and imported by me, have what SketchUp calls “guide points” at the center of each connection. These guide points apparently make cross hash marks in Layout viewports.