How can I keep actor references from being lost when I reload a map?

What I want to make, is that when you die, most of the level in my game resets, except for some actor in the level that acted as doors (so if you opened one in the game, after you die, it should still be open). So what I thought I could do was save the actor references in an array in a game instance and then reload the map with “open level”, but apparently it doesnt work like that. I can store actor references in the game instance but they get deleted after I reload the level. Ive checked this by using print strings, during play, I open a door, check the array on the game instance and the reference is there, I die, check again, and the reference is lost. This only happens whith actor references, all other variables stored in the game instanced are still unchanged after i reload the level. How can I keep references from being lost when I reload a map?