Can't walk through across certain half-slab in nether at 106 / 6.5 / -28

There is this one block in the nether that I can't seem to walk across. I just laid down some cobble half slabs, and if I try to walk across this one location, I get stuck like it thinks I'm trying to walk through a wall. If I keep holding down W to try to push through, I start to take damage.

I know this is a really vague bug report, but I'm just going to have to answer questions.

If walk towards negative Z at 106.177 / 6.5 / -27.749, I get blocked like I'm hitting a wall.

Same thing happens if I'm facing positive Z and try to move forward from 106.357 / 6.5 / -29.306.

If I face positive X and try to move forward from 105.688 / 6.5 / -27.830, this happens.

And I can experience this problem if I face negative X and try to move forward from 107.307 / 6.5 / -28.051.

There's nothing there. I mined it all out, and I can walk around in circles around this spot with no problems. I also can't move into this spot backwards or sideways. It's like I'm running into an invisible wall. And what's really weird is that I take damage when I push it.