For some reason, even though a zombie has my armor/items, it despawns afterward. Just to make sure, I gave it a helmet and put it in a hole and covered it up, yet when I checked later, it disappeared.
Comments 5
I was not able to replicate the described problem. If what you are saying is true, it is indeed a bug (source). You might want to include some additional information such as your operating system and circumstances, e.g. gamemode, difficulty and single- or multiplayer.
Note that the wiki is maintained by volunteers and only describes the current state of the game, so not everything on there might be correct / intended.
You need to give it a name tag if in Survival or give it the PersistenceRequired tag in the nbt for the command if in creative. Giving it items, as far as I am aware, does not work.