Continuity mistake: When the Rebel fleet arrive at Scarif, they arrive close to the shield gate and the Imperial fleet. However, when Blue Squadron makes their attack run, they are suddenly high above the shield gate. (01:38:05 - 01:38:40)
Plot hole: Revelations in this film create a potential plot hole in Episode IV, in which Vader says Princess Leia is his only link to learning the location of the Rebel base. In this film, Vader captures the Profundity (Raddus' command ship), which is transporting the Tantive IV in its cargo hold. Vader then watches the Tantive IV fly away with the Death Star plans, leading into the beginning of A New Hope in which he captures that ship. So, the first question is, were there no survivors of the Profundity Vader could interrogate to learn of the location of the Rebel base (assuming the navicomputer has been scrubbed). Even if the entire crew were killed, in A New Hope we see several crewmembers of the Tantive IV have been captured. This film shows that the Tantive IV was at Yavin prior to the battle (evidenced by R2-D2 and C-3PO in the hangar). That then raises the question of why Vader couldn't have interrogated those other crewmembers to learn the location of Yavin as the Rebel base.
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.
Continuity mistake: When Vader appears at the end, the amount of rebel soldiers facing him changes throughout the scene from about 8-12 as Vader makes his way through them.
Continuity mistake: When K is at the control panel he shoots two stormtroopers to his right. He then says stardust and moves his aim slightly to his left and shoots the same two stormtroopers again - the first two stormtroopers have disappeared from the floor.
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.