Swift Combine sink returns demand .none

Question

I have the following code to listen to an ObjectBox query:

query.publisher
     .mapError(DatabaseError.other(nested:))
     .eraseToAnyPublisher()
     .map(mapEntities(_:))
     .catch(handleError) // Returns Empty<[..], Never> but also tried Just<[...]>
     .receive(on: DispatchQueue.main)
     .sink { results in
         self.allEntities = results
     })

• I have the eraseToAnyPublisher part because up until that part the code is in on other function I removed for simplicity
• I save the returned cancellable

After the first values are received, I can see logs from object box that say Unsubscribe. I've checked the source code and it seems like this happens when the subscriber returns demand .none but I can't figure out why this happens