A lead can be attached to a dolphin when a lead is already attached to it

The bug

You can attach a lead to a dolphin when a lead is already attached to it. Not a duplicate of MC-96347.

Steps to reproduce

1. Attach lead to dolphin
2. attach lead to fence
3. Attach lead to dolphin

With any other mob it doesn't let you.

If you are in survival mode, it destroys the original lead.