I just went and re-read Ornn and Braum's lore, and something bothered me. If the door was never made to be opened, how did the troll boy open it in first place? Ornn made it so that it cannot be opened? Did Lissandra do something to the door?
That's been bugging me too, it could just be that the absolute "cannot ever be opened" is a product of retelling the fable and hyperbole that comes from the story being passed down. Or maybe the troll boy that broke in was descended from the one that asked to have it built in the first place.
Its likely lissandra enchanted it, seeing as ornn originally made it without any intent on it being magical (seeing as he hates magic), and it's magic is ice. However, it could also have been left open to chameo a future champion. If you think about it, even if lissandra did enchant it thereby weakening the material and allowing it to be opened in the instance of the troll boy, braum couldn't even open it after the fact. So why did it open, did it even open? Did the troll boy get in another way?
The thing is since Braum's color text is a folk story, you shouldn't take it to seriously. The most lore we have loves to use the unreliable narrator. Same goes for the Braum color story. It probably didn't happen like this, but people believe it did. On the other hand - Braum was released on the time there the narrator team wasn't sure what to do the with lore and it is probably outdated and not 100% reliable in the new canon.
Lissandra may have lured him, then teleported him inside.
