When I go to the book details web page reference fields are shown as cryprical ID (e.g. category: "a0149a85-2976-44f5-9dbf-aa7a7cfe5304").
It seems that this only occur on single reference fields. Fields with multiple/list references (e.g. authors or publishers) are shown correctly.
Furthermore: The problem only occurs for users with read-only access to the field.
If I grand write access to the user, e.g. the category is shown correctly as dropdown box.
On the books overview the fields are shown correctly even if there is read-only access right.