I'm curious what the configuration was since they didn't show a picture. Did the plane have to pull up sort of parallel to the terminal to allow the use of 2 gates' jetbridges?
I know at some California locations where you have to go outside to board (LGB, BUR), Southwest boards from the front and rear (with a roll-up ramp at the front, and roll-up stairs in the back). I believe at SJC, pre-covid they had a trial run of boarding from the front and rear - with the front using the jetbridge, and the rear using roll-up stairs (and presumably either walking up stairs to the jetbridge or another set of stairs to the terminal). It'd be interesting to see this tried in more places - even if just for the novelty factor!
According to the tweet from the article, they used B5 for the forward half and B3 for the rear. Given the position of the jetways of these gates at CVG, this is probably something that could only be done with this kind of orientation, so they wouldn't just be able to do dual boarding with any two adjacent gates. You can use Google Maps to pull up how they are oriented and picture where the plane would go. The article also shows another tweet with a picture of LH appearing to use dual jetways for an A321.
Then there is also AMS which is probably one of the last airports to still have I think 2 gates with overwing jetways.