I was making a minecart ride meanwhile I was shooting mobs with a bow. When I saw a pig under me, I shot the bow and the arrow instead hit and destroyed the minecart! This also happens to boats.

The way to find the bug is:
1. Make a small lake and put the boat inside it or make a small minecart circle and put the minecart in it. Include whatever kind of rail.
2. Gather a bow & arrow
3. Shoot the boat/minecart and it will be destroyed.