Set TSet node works like Add node under for loop in BP. But TArray is not

Development Programming & Scripting C++
1

With below,

void ARep02GameModeBase::TArrayTest(int32 InNumber, TArray<int32>& OutArray)
{
	OutArray.Add(InNumber);
}

void ARep02GameModeBase::TSetTest(int32 InNumber, TSet<int32>& OutSet)
{
	OutSet.Add(InNumber);
}

I made this Blueprint function,

n1
n11920×1282 192 KB

And when I run this, I got:
n2

I can guess why this happen. But - Should I look this is intended?

You can see full code in here : GitHub - cutycutyhyaline/UE4TMapAndTSetWithForLoop

And here are additional tests : https://hyaline.com/2021/09/01/in-blueprint-for-loop-set-nodes-for-tmap-or-tset-work-as-add-node/