How to reproduce:
1. Open the attached project (AddressablesTest.zip)
2. Build Addressables
3. Move the generated bundles/catalog to http://localhost/Editor/
4. Open "AssetLoader" Scene and enter the PlayMode

Expected result: No errors or an error that explains the issue appears
Actual result: Addressables.InitializeAsync - Unknown error in AsyncOperation error appears

Reproducible with: 2019.3.6f1, 2020.1.0b2, 2020.2.0a3
Reproducible with Adressables Package version: 1.5.0,1.5.1, 1.6.2

Notes:
- Could not test on 2018.4 and lower versions
- Could not test on Addressables Package version 1.4.0 or lower because of dependency errors
- After the `InitializeAsync` call, the error occurs, mentioning the catalog hash file despite the "Disable Catalog Update on Startup" option is enabled