Jumping on a boat in water for a while causes you to accumulate fall damage

The bug

If you jump on a boat inside water for a while and then jump on the ground you will take fall damage depending on how long you were jumping.

How to reproduce

1. Place a boat in water near land
2. Hold down space on a boat for 3+ jumps
3. Jump from boat on land
   → You will take fall damage and can even die from it

See video bug.mp4

Note

Does not happen if the boat in not inside water.