Mcpe Wither Skeleton Shooting Arrows

I was going through a nether fortress and happened upon a blaze spanner, being unprepared I turned away and saw a wither skeleton, and for some reason rather than attempt to hit me with it's sword it shot arrows at me

What I expected to happen was...:
The skeleton should have tried to attack me with it's sword

What actually happened was...:
It shot arrows out of its hand

Steps to Reproduce:
1. Wait for a wither Skeleton to spawn
2. Aggravate
3. ...