How to reproduce:
1. Open the user's attached project ("BugAddressableAssetPostprocessor.zip")
2. Open "Window > Asset Management > Addressables > Groups"
3. In Groups window press "Build > Clean Build > All"
4. In Groups window press "Build > New Build > Default Build Script"
5. Open folder "Library\com.unity.addressables\aa\Windows\StandaloneWindows"
6. Copy samplescene_scenes_all*.bundle to a new folder and call it 1.bundle
7. In the Groups window press "Build > Clean Build > All"
8. In the Groups window press "Build > New Build > Default Build Script"
9. Open folder "Library\com.unity.addressables\aa\Windows\StandaloneWindows"
10. Copy samplescene_scenes_all*.bundle to a new folder and call it 2.bundle
11. Change the Aspect ratio in GameView
12. Change the Window Layout in the Editor
13. In the Groups window press "Build > Clean Build > All"
14. In the Groups window press "Build > New Build > Default Build Script"
15. Open folder "Library\com.unity.addressables\aa\Windows\StandaloneWindows"
16. Copy samplescene_scenes_all*.bundle to a new folder and call it 3.bundle
17. Perform a binary compare, under windows use "fc /b 1.bundle 2.bundle" on the command-prompt
18. Perform a binary compare, under windows use "fc /b 1.bundle 3.bundle" on the command-prompt

Expected results: Build System outputs bitwise identical bundles if the source content did not change.
Actual results: The generated bundles are bitwise different.

Reproducible with: Addressables 1.16.10 - 1.16.15 (2019.4.17f1, 2020.1.17f1, 2020.2.0b12, 2021.1.0a1, 2021.1.0a4)
Not reproducible with: 2020.2.0b13, 2021.1.0a5
Could not test with: 2018.4.30f1 (Couldn't downgrade)