LoadPackage succeeds, FindObject then fails?

I have an ULevelSequence at “/Game/Path/ALevelSequence” that I load as a UPACKAGE using LoadPackageAsynch, and I store it as a UPROPERTY():

LoadPackageAsync(IntroSequencePath, FLoadPackageAsyncDelegate::CreateUObject(this, &UTS_MapResourceHolder::OnIntroSequenceLoaded), 0, PKG_ContainsScript);

When this succeeds, it is placed in a IntroSequence UPackage pointer. When I want to use this, I do:

return FindObject<ULevelSequence>(IntroSequence , TEXT("ALevelSequence"));

when I cook and run the game (not in editor, stand alone), The package load succeeds, but the FindObject fails. Can someone explain what I have done wrong here?