If you get a dog, you can name it Arrakis. If you have a baby, you can name that Arrakis too. Even if you've already named a dog that. But a dungeon?
This general issue applies to more than one dungeon, to be clear, and I absolve none of these litigious self-important people who have nothing better to do than stand athwart the use of culture and language for its natural purpose (looking at you, Tolkien family; looking at you, too, Disney), but I got called in across the pond for this dungeon when it appeared in Casablanca, because one can operate there on French if necessary and my power set works pretty well for evacuating the surrounds (the monsters are attracted to things they can detect, such as Not Me). And someone bothered to tell me, in my briefing before I went to haul people away from gigantic sandworms:
"Please use the formal name of the dungeon, Infested Wasteland; we have been asked to respect the integrity of the temptingly similar media property."
This is right next to estimates of how big the worms are! Right next to an explanation of the search procedure for the interior of the dungeon on the core hunt! Right next to a list of the fellow responders I'm about to trust with my life and vice versa! If I recall correctly, it showed up before the map of Casablanca! The integrity of the temptingly similar media property was right on there among these mission-critical details.
Fuck the integrity of the temptingly similar media property. It's not worth two syllables, let alone two syllables and a speck of professional attention under time pressure. Come at me, Frank Herbert's shambling undead legacy. The thing is a sandstorming desert with tunneling gigantic worm monsters that detect vibrations, and I'm calling the place Arrakis. Nobody but nobody says Infested Wasteland unless they are doing speech to text with a very persnickety database that (because they have been asked!) pretends that names don't mean what people use them to mean. Frank Herbert's estate, as of this posting, you've been asked to retract this asinine request and respect the integrity of the deadly work dungeoneers do every day. No one is singling your particular media franchise out. Dungeons pick up ideas and you can't sue them; implying that we're in legal danger for noticing this has happened solves nothing. You don't see the heirs of Theodore Giesel behaving in this embarrassing fashion. The LEGO Group has a really lovely victim fund for anyone who winds up in an obvious Lego dungeon and they have stopped doing the thing where in addition to money they sent a box of bricks.
(This having been said, I think "Dunegeon" is in slightly poor taste both because it's easy to misread/mishear for precisely the reason it's a tempting pun, and because it has the "sonic hedgehog gene" problem where you wind up telling very upset people that their family tragedy is due to this silly-sounding thing.)