Bezray

 You have mods installed. We don't know if it is a mod causing it. Remove them and see if it works.

I would say that this is Works as Intended. Boat mechanics are not a glitch, and this is just boat mechanics working as intended. Mojang programmed the boats to be this way, and that's the way they are. Now whether this should be something that happens is a matter of debate, but this is not a bug.