When using HideInNonPrefabs on a field, the field works properly on prefabs when selected in the project view, but does not work when opening the prefab in Prefab Stage. This is probably because technically in Prefab stage the prefab isn’t actually a prefab (because Unity’s behaviour there is quite odd), but the expected behaviour is for the field not to be hidden in this case.
How can we reproduce it?
Create a class with some field, mark it with HideInNonPrefabs attribute, create a prefab, then open the prefab in Prefab Stage. Notice that the field is not shown.
What version of Unity are you using?
What version of Odin are you using?
2.1.12. Notice that 2.1.12 does not appear in the list of versions, so I picked 2.1.11 instead.
Do you have Editor Only mode enabled?
What operating system are you on?
An example component:
When selecting a prefab with the component in project view:
When editing the prefab in Prefab Stage