Regression: Next: Bordering FoF blocks will not render fully

If an FoF borders another FoF in a neighboring sector, the bottom of the larger FoF will not render, but the top part will render as expected.

Example map.MAP01.wad

This regression began appearing in Next builds around two weeks ago. This is tested with the latest build of Next. Also to note is that collision is not impacted by this, just visuals.