In Episode 3: Revenge of the Sith, Mustafar is a volcanic planet filled with lava.
While in Rogue One, the skies are different and the lava is not that scattered anymore.
Is there any information on why Mustafar is different in these two films?
Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.Sign up to join this community
Since Mustafarian mining involves extracting minerals from the lava, it needs to be near an open and active lava flow.
The lava on Mustafar wasn't as hot as normal lava, this was due to unusual mineral allotropes that are molten at lower temperatures.
The planet's native Mustafarian species lived in underground caves created by lava fleas as they ate through the planet's crust, and made their armor from the heat-resistant shells of the creatures. Only venturing up to the surface in order to collect valuable minerals from the lava flows.
Mustafar - Wookiepedia
Vader's castle, on the other hand, has no such requirements.
Darth Vader constructed his own castle, a testament to his might, at the site of his greatest defeat: the fiery lava-world, Mustafar. The location and design of the castle came as much from the dark side as it did from Vader's personal history, however; the complex sits atop an ancient Sith cave, and the tuning towers serve as a conduit for the dark side of the Force.
Darth Vader - Star Wars Databank
Even though it says the castle was built "at the site of his greatest defeat", it is important to note that it means the planet, not literally the lava bank on which he lost 3 limbs.