Feels like a bug, but - I was in Maulwood, guaranteed Strongroom key. I found the Horadric Portal to the strong room, cleared it… then went back to finish the Maulwood dungeon, came across a second Horadric portal, it let me interact with it, and fight the waves to summon the portal - here I’m thinking - WOW 2 in a single dungeon! what luck! what fortune!
I entered the newly formed portal, only to find, I was in the same already cleared Strongroom, and double the disappointment, I was at the start, with no easy way to return to Maulwood, other than to run through the now empty strongroom to the exit portal - such a waste of time.
Like I said, feels like a bug.