Can't use shield in Offhand after using water bucket in Main Hand

Steps to reproduce:

1. Place a shield in the offhand;
2. Equip a bucket in the main hand;
3. Use the bucket to pick/place water/lava;
4. The shield is now unusable.

A quick fix is just to re-equip the shield. 

I Recorded myself reproducing this bug, but the file size was too big to upload it here, so I just uploaded it to [YouTube|https://youtu.be/ggqBFyGHrjE]