Why is my UObject being GC'd?


So i am trying to instantiate a UObject at runtime using NewObject like so:

    Group->Pattern = NewObject<ULightingPattern>(GetTransientPackage(), Group->PatternClass);

I am marking the variable as a UPROPERTY, so as i understand it, the garbage collector should know when i am referencing this UObject:

ULightingPattern* Pattern;

The problem i have is after a certain amount of time, this UObject is being destroyed or marked as invalid and i get a crash at this point:

// Update visuals
if (!IsValid(Group->Pattern))
    continue; // Only skip this group

I cannot see any reason why this is. I have checked to make sure it is definitely the GC that is destroying the object, by creating the object with the MarkAsRootSet flag, which appears to fix this issue, but then the editor crashes when ever i try and exit the game as it cannot destroy the object.

If it helps at all, the UObject is being reference from a USTRUCT which is referenced by value from a UActorComponent like so:

struct FLightingGroup


    ULightingPattern* Pattern;

UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class POLICE1013_TECH1_API UEmergencyLightingComponent : public UActorComponent


UPROPERTY(Category = "Settings", EditDefaultsOnly)
TArray<FLightingGroup> LightingGroups;

It seems switching between GetTransientPackage() and this has fixed the issue