Reproduction steps:

1. Open "TextureRefExample.zip" project
2. Open the Profiler Window
3. Build the Player with "Development Build" and "Autoconnect Profiler" enabled
4. Launch the Player
5. Click on "Memory" field in the Profiler
6. "Simple" -> "Detailed"
7. Take a Sample
8. Expand "Assets"
9. In the Player click on the "Load prefab" button
10. Take another Sample
11. Notice that "Texture2D" appeared, which includes "test_texture"
12. In the Player click on the "Unload prefab" button
13. Take another Sample

Expected Result: The "Texture2D" "test_texture" object dissappears
Actual Result: The "Texture2D" "test_texture" object stays

Reproduced with: 2019.1.0a2. 2018.3.0b3, 2018.3.0a10
Did not reproduce on: 2018.3.0a9, 2018.2.10f1, 2018.1.9f2, 2017.4.12f1 (Addressables only work from 2018.3.0a10)