Recently I'm just playing Minecraft, and ride a boat, explore some places... and when I exit the boat and jump a couple of time, I started to lost hearts and then I died. And the message in chat said that I fell from a high place. I was in a boat and there was no one there no mobs or anything just me. Please fix this bug Mojang.

Minecraft Java Edition - Vanilla

Survival - 1.14.3