Left clicking leash knot in creative drops lead items whereas right clicking it does not

The bug

When you left click a leash knot a lead item is dropped, however when you right click it no item is dropped.

Expected behavior

The lead item should not drop when left clicking a leash knot.

How to reproduce

1. Leash a mob to a fence

2. Right click the leash knot
   → No lead item should drop

3. Leash a mob to a fence again

4. Left click the leash knot
   → A lead item drops