When an entity is named normally they will have a persist tag and will not despawn if you go out of chunk-loading distances.This isn't however the case for entities that were named before then transfurred.Despite keeping their original name,they will despawn as soon as you go out of loaded chunks like other hostile mobs.I am unsure if this is an intended feature or a bug,but it most likely seems to be a bug.

It's rather easy to reciprocate.
-Have a named humanoid entity
-Have them transfurred
-As soon as you go out of the render/simulation distance,they should despawn like any other hostile mob.