Sniper collisions are weird when fired in a 2-block tall space

[DiamondWalker]

https://streamable.com/auhr2j

As you can see, very annoying and unpredictable bug. It's affecting my ability to safely use the mob farm in my survival world. I can't determine the exact cause; the video makes it look like it's caused by being near the wall but I don't think that's it. Maybe it's the distance to the target?