How to reproduce (only works in creative) :
1.Get any type of sword.
2.Get a bow
3.Make a shoot with the bow.
4.Open your inventory, from the sword hotbar location, change it to the bow location (using the hotbar keys).
5.Make another shoot with the bow (nothing will happen, but don't jump over this stage).
6.Change the bow back to their previous hotbar (again, using the hotbar keys).
7.Exit from the inventory and right-click with the sword to block (you will able to shoot with, if not, watch the video, it will help you).
This bug will cause :
1.Destroy blocks with the sword.
2.If you save the world, and enter back, the glitched sword will be a bow.
3.Make less damage when HITTING with the sword, NOT when shooting with arrows.