Bug Inspector deselects gameObject and closes when any value is changed in the inspector.

This is an intermittent (but persistent) bug: The inspector will just clear itself and deselect whatever you have currently open whenever you change a value in it. If I reset the window layout to "Default", that temporarily fixes the problem, but it inevitably shows up again.

This is possibly related to the Addressables package; it cropped up after I installed it. It also seems related to if/when you have the Addressables Groups window open, but I have it open a lot so it could just be a coincidence...

 

Update: This always occurs after building the Addressables groups.