Fortune 2 book crashes realm when used to punch mobs.

Gigaset QV830
Android version 4.2.2

Standing at a skeleton XP farm I made, I had an enchanted book of Fortune 2 in my hand. As the skeletons fell 21 blocks I started to punch them, with the book. After around 3, up to 10 skeletons died the entire realm crashed. Two people on the realm at the time, we tested why it was the realm kept crashing. Only time it did was when I went to try and kill the skeletons with that fortune 2 book in my hand. Happens every time I try it now.