Death by jumping on boat too much

I was jumping on a boat on Easy difficulty to get my hunger down to eat a suspicious stew, and died, saying I died of fall damage. I think when coding the game, the boat is seen as something you can stand on, but not ground if that makes sense. You don't take fall damage by jumping up and down in place on GROUND, but you do on something you can stand on, that ISN'T considered GROUND.