Judge Aileen Cannon is asking the Justice Department and Donald Trump co-defendant Walt Nauta to weigh in on the legality of special counsel Jack Smith’s ongoing grand jury activity in Washington, DC, which relates to the obstruction portion of the Mar-a-Lago documents case before her in Florida.
You can’t dismiss with prejudice because of a simple jurisdictional issue like that. “You should have filed it somewhere else, but now you can’t file it anywhere”. Prejudice means that the case has no merit and saying you should have filed it somewhere else indicates it is possibly meritorious.