Missing a slam, due to bad definitions

[ThorvaldAagaard]

CBABED49435683E8E17A449BE423

4H with an Ace and trump queen is wrong - and the hand also fit the actual description for 3H

But let us change Norths bid to the correct 3H

Now we have the problematic 3N, that just show extra, but unspecified how to continue.
BBA now think the North hand is worth a cuebid

South now ask for acces, but forget to ask for trump Queen (knowing we have 10 trumps it is not needed), and the lay down slam is missed.
Playing with GIB/BEN on BBO North signs off in 4H

But that does not stop South, that now just bid the slam after getting 1 Ace

So why is South bidding 3N if any bid will be followed by 4N?

To me a 4N bid seems obvious