setting managedObject's relationship value will occur error like 'Illegal attempt to establish a relationship ‘u’ser between objects in different contexts in NSBatchInsertRequest

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How can I make my app support this recommendation? Is there any relevant documentation?

I donate some INPlayMediaIntent to system, and I find them in Control center, when I click one of them to play media background, the handler don't execute resolve method, I wanna resolve some mediaItems for suggestion playlist