Legendary trining lamprey follower dies and results in regular trining lamprey

I got a sultan box that fabricates a follower. This one was for a trining lamprey. It created a legendary lamprey as my follower and it then spawned two regular lampreys as its other two components. The other two died and respawned fine, but when the legendary died, it resulted in a regular trining lamprey spawning not the legendary one.

Don't know if this is intended.