The bug

Boats will glitch out where they will visually look like they're still moving forward but the player gets stuck in the position where the boat is supposed to be. If you do end up escaping the glitch, jumping on top of it will once again make the player stuck. The visually glitched boat has no hitbox whatsoever and will clip through any block in front of it.

To reproduce

There seems to be no way to reproduce this glitch reliably as it just happens by chance, but it happens when you try to shift out of a moving boat and you'll know it happened because the boat seemingly moves forward on it's own while the player gets stuck on top of the "boat".