Texture cube references appear to stay in memory

Texture cube references appear to stay in memory after they have been added to a blueprint. They continue to take up memory even after the variable reference has been deleted.

1. Open a first person shooter template
2. Play in Editor
3. Press the '~' key to open the console
4. Type Stat Streaming and hit enter
5. Make a note of the memory usage for non streaming textures
6. Stop PIE
7. Create a new actor blueprint
8. Create a new TextureCube Reference Variable
9. Set this to be an array
10. Add 4 elements to the array
11. Set Show engine content to true
12. Set each element in the array to a different cube map
13. Save and compile
14. Play in Editor
15. Use the command again
16. Notice that even though the actor has not been used and the variable has not been placed in a graph that the non streaming textures memory has gone up
17. Stop PIE
18. Delete Variable
19. Save and Compile
20. PIE again
21. Use the Command Again
22. Notice that the memory usage has not gone down

Expected: The usage would only go up if used
Result: The memory usage goes up even though the textures are not yet in use