Some attributes are not ignored when user would like to do update of object.
Use case:

• user read object via "/admin/api/cms/X/ {id}.json GET"
• change/add some attributes
• try to update object via "/admin/api/cms/X/{id}.json PUT"

The update fails because some autogenerated attributes are not ignored in PUT. I think this is wrong because user should remove them before updating the object and attributes like these are ignored in other PUT API endpoints.

File PUT autogenerated attributes: "created_at", "updated_at", "url", "title", "content_type"
Section PUT autogenerated attributes: "created_at", "updated_at"
Partial PUT autogenerated attributes: "created_at", "updated_at", "published"
Page PUT autogenerated attributes: "created_at", "updated_at", "hidden", "published"
Layout PUT autogenerated attributes: "created_at", "updated_at", "published"