Other mistake: Director Krennic is shorter than Tarkin in their scene together. Krennic comes up to Tarkin's ears at best. Krennic is also shown to be about the same amount shorter than Darth Vader, roughly coming up to Vader's ears as well. But as shown in A New Hope, Tarkin is considerably shorter than Darth Vader. So by what was shown in A New Hope, Krennic should be much shorter, perhaps coming up to Vader's chest.
Other mistake: When Rogue One's team runs onto the beach after the AT-ACT follows them at the beginning of the scene it shows Stormtroopers walking next to them on the beach, but that's impossible due to the fact that all the AT-ACTs (excluding one who is moving in the water at the background) are still moving through the trees. (01:40:25)
Answer: Yes. They were on their way to the starport when they were encountered. They left the planet a short while later, before the Death Star attack.