After years of speculation from fans and some worries that it might be a plothole, Square Enix has finally confirmed that Aerith has memories and visions from the future that she shouldn't have in Final Fantasy 7 Remake, and that the Whispers are actively taking them away from her.
It's fair to say that Final Fantasy 7 Remake's plot can be a bit confusing at times, especially considering it rewrites and moves away from the original game in some significant ways. Combine that with it seemingly having multiple universes and all of the convoluted content from Compilation of Final Fantasy 7 and it's no surprise that fans are still asking questions several years after the game's original release.
One particular thing that's bugged fans for some time now is how Aerith has knowledge of events that haven't happened yet and how she's able to peer into the future. An example of this is when she and Cloud meet again during Chapter 8 and Aerith calls Cloud a mercenary, something she shouldn't know. It's explained away by her saying that she guessed it because of his Buster Sword, but it's far from the only time that it's made clear she knows things she shouldn't, such as her knowing Sephiroth is alive and that the Sector 7 plates are going to fall.
There are several more examples of this throughout the game that make it clear that Aerith is more aware of what's going on than the others. Well, after years of speculation, Square Enix has finally outright confirmed that Aerith does have memories that she shouldn't and that she's not actively trying to hide the truth from people. As reported and translated by Silliconera, the Final Fantasy 7 Remake Twitter account answered the question directly on Twitter a few days ago, putting some of the theories to rest.
In the tweet, it explains that Aerith has pieces of memories that she shouldn't from things that haven't happened in the timeline yet, such as knowing the name of Cloud's Buster Sword, knowing where Cloud's going before he's told her in, and being aware of Tifa wanting her to save Marlene, among other things.
The tweet also explained that every time Aerith encounters the Whispers, they take some of those memories from her, which is why she only knows certain details. Aerith also seems at least a little aware of what's happening, as at one point she says, "Every time the Whispers touch me, I lose something. A part of myself", which now seems even sadder when you realise she's not purposefully trying to be vague.