Putting end rod on leash knot makes end rod disappear from bottom bar but the end rod still exists, but invisible

Steps to reproduce:

• having a end rod in your inventory, right click on a leash knot on a fence

• the lead is now connected to the player

• the end rod disappears from your bottom bar

• right click on the fence, the lead is now a leash knot

• give a end rod from the command line

• 2 end rods are now in bottom bar