When scene is reloaded (for example changes are saved) "Missing (GameObject)" ARRAY references are set to "None" (GameObject).

STR:

1. Open user attached project
2. Create new Cube in hierarchy
3. Drag it into Go Array Element 0 and 1(Component of GameObject)
4. Delete your newly created Cube.
Notice that Go Array[0] & Go Array[1] are now shown as "Missing (GameObject)"

5. Change transform of GameObject a bit
6. Save the scene.
Notice that Go Array[0] & Go Array[1] are now shown as "None (GameObject)"

Expected Behavior: Go Array[0] & Go Array[1] are now shown as "Missing (GameObject)"

Reproduced with: 5.3.5f1, 5.4.1f1 5.5.0b10

Verified with: 2018.3.0f1