Hitting a mob while swimming makes you stop swimming

Hitting a mob while swimming makes you stop swimming

What I expected to happen was...:
Keep swimming

What actually happened was...:
Hit the mob causes stop the swimming

Steps to Reproduce:
1. Stay underwater where have a mob;

2.  Start swimming (Ctrl + w)

3. Hit an mob (squid, fish, even a pig...) while swimming;

4. The bug appears here.