first, let’s assume you did not try to save the returned value of the MVO request in a parameter in any way, because that may cause problems like you described.
Here is a tutorial on how to correctly implement an MVO object, and how to link it to a placeable object via LIBRARYGLOBALS request.
Here is another article about the topic, in general.
In case the articles do not give you a solution to your problem, we can discuss this further.
Library Developer, Library Team