Deadline recently broke an exclusive article in regards to the production of the Dune movie. Specifically, the cast and crew are headed back to Hungary for additional filming. Hungary was more than likely used for interior shots.
The actor portraying Leto Atreides (father of Paul Atreides), Oscar Isaac has stated:
We’re going to do some additional shooting in mid August… they’re saying in Budapest in Hungary, I saw some things cut together and it just looks amazing. Denis [Villeneuve] is a real artist and it will be exciting to see it come together. It’s kind of wild that we’re doing some additional shooting a few months before it’s supposed to come out, but that happened with Star Wars as well. — Deadline
Oscar Isaac has described the movie as ‘nightmarish’ and ‘brutalist’ previously:
I couldn’t imagine anyone more suited for the tone of the original Frank Herbert novels than Denis. There are some things that are — for lack of a better word — nightmarish about what you see… There’s just this kind of brutalist element to it. It’s shocking. It’s scary. It’s very visceral. And I know that definitely between Denis and myself and Chalamet and Rebecca Ferguson as the family unit, we really searched for the emotion of it. I’m beyond myself with excitement. I think it’s good to feel cool, unique, and special. — Collider
This is nothing out of the ordinary. Large epics typically have reshoots after the initial filming simply to refine and improve the movie. This is no cause for concern and the team will take extensive safety measures in light of the virus pandemic. The movie is still designed for a December release.