Picking up an axolotl with a lead attached destroys the lead

When an axolotl with a lead is attached to a fence, clicking on it will destroy the lead (i.e. it will not drop).

Steps to reproduce:

1. Place a fence
2. Spawn an axolotl
3. Click on the axolotl with a lead
4. Click on the fence with an empty hand
5. Use a water bucket on the axolotl

This bug happens weather or not the axolotl is on land or not. Clicking on the fence with the lead on it after picking up the axolotl doesn't do anything but remove the lead from the fence and not give it back.