Decoding 'userFram' errored with: readStartDocument can only be called when CurrentBSONType is DOCUMENT, not when CurrentBSONType is STRING

Working with Data Java Frameworks
1

Failed to decode ‘Profile’. Decoding ‘userFram’ errored with: readStartDocument can only be called when CurrentBSONType is DOCUMENT, not when CurrentBSONType is STRING.

Fail point seems to be:
public T get(String id) {
    return collection.find(eq(new ObjectId(id))).first();
  }