Addressables AssetReference "None" value is not saved in Editor when used in Prefab

[aka3eka]

1. There is a public field of Addressables.AssetReference type in MonoBehaviour component. This component is attached to a GameObject that is converted into prefab. Then prefab instance is added to the Scene. Changing field value to anything except "None" (empty) works fine. But after the value has been changed to anything it can not be changed back to "None" (empty value). Changing value inside of the Prefab to anything except "None" partially solves the problem, but that's not a solution because it forces the prefab to keep reference to some object. 

2. Steps to reproduce: 2.1. Open project attached. 2.2. Open the SampleScene and select ObjectWithReference instance on the Scene. 2.3. In Inspector change value of field "Asset Reference" to "None". 2.4. Save the Scene. 2.5. Reload the Scene. 2.6. Select ObjectWithReference instance on the Scene. 2.7. Result: the value is not "None" but the reference to the object that was set before. Expected result: the value is set to "None".

[kirstenpilla]

Hi @aka3eka if the issue is still reproducible in the latest package version, I would recommend submitting a bug through the regular submission process https://unity3d.com/unity/qa/bug-reporting

I can't seem to reproduce the issue on a new project in Addressables 1.19.17