Minecraft Username: LimeLush Brief Description: Placed a magic dolphin (ghostly) spawn egg in a sealed enclosure with water and air access in a region with damage animals set to deny and invincibility set to allow. Dolphin went poof. Instructions: Placed Magic Dolphin (Ghostly) in the conditions listed above. Logged out. Logged back in, Dolphin gone. How many times did you recreate this?: Once Result: Dolphin Despawned Expected Result: Dolphin Not Despawned
I am able to re-create, but so far only with un-named dolphins. Any dolphins I have named with a name-tag are not despawning when I move out of the area or log off. I would suggest naming your Dolphins with nametags in the future.
As mentioned above, this is likely simply because you did not name tag the dolphin. Be sure to do so in the future to avoid having mobs removed by our automated cleanup.