The outliner shows duplicate objects in different collections grandpa_for_baking_high and grandpa_for_baking_low in the Casual_outfit_baking collection and the [grandpa_baking_to_casual].
I can’t remove grandpa_for_baking_high and grandpa_for_baking_low from Casual_outfit_baking collection, even when I bring them to the Scene Collection
AFAIK this is the feature of collections: one object can be in multiple collections.
In Object Properties where the name of the object is on the right is now a 2 for your grandpa object because it is used two times but the same data.
If you don’t want it in the other collection just click the X in Object Properties → Collection… name of collection
Or right click in the outliner on the object line you want to take out of the collection > Unlink
Ah yes thanks… i have to look more at the outliner… mostly always (if at all) just using to select something… i learned something again today 
@Okidoki @Gorgious Thanks for your answers. I think sometimes the outline gets a lot confusing and I just can’t get it to look organized. I really like Maya’s outliner organization. That why I bought the Hierarchy To Collections add-on by BoUBoU. This addon can organize the outline like Maya but it can also make Maya like collection organization into Blender like collections.
Here I used this addon and it created a separate hierarchy for the objects in SELECT_EmptiesHierarchy_Scene Colection in the Asset_Root_Scene Collection
As you can see the camera object (and all the other nom-null objects) are only added to one collection in the collection menu in object properties. When I press X there the object is simply deleted.
I wonder if there is a way to have only the Asset_Root_Scene Collection with the objects and delete all the SELECT_EmptiesHierarchy_Scene Colection
