Scientifically, the reason it happens is something like short term memory being confused with long term memory. Something like that.
What bugs me is that it totally fucks with my perception of reality. My brain keeps telling me "this exact thing has happened before", but I know that's not the case.
I just saw a something on twitter that feels like I saw it before I even had an account there. Then the same thing happened for me realizing it's just Dejavu, and getting annoyed by it. Then looking at the tweet above it, and getting even more annoyed that I remembered that as well. I even remember switching tabs over to Phuks so I can complain about it, but luckily that's where it stopped.
But it never fucking happened, and it drives me so fucking insane. Whoever designed the OS for the human brain needs to patch this right now or I am going to lose it.
It hasn't. I do know what's coming slightly before it happens, but only for decisions I know I am going to make. Like, I knew I was going to look at that other tweet, and I knew I was going to go to Phuks to complain slightly before I actually to do those things, but I couldn't predict things like what the content of the tweets would be, or what would be on the Phuks front page when I switched tabs. It's just enough of a delay that I can barely notice it, but I wouldn't be able to announce it or anything.
What you describe is pretty interesting. I used to think I could possibly train myself to have that, but then I didn't think it was possible.
If you can actually tell people what's about to happen, how much of a delay do you have between the initial moment of Dejavu, and the thing actually happening? Can you see things that are out of your control, or only actions you've decided to take? Are you sure you aren't just having a Dejavu for something that is going to certainly lead to something else, or is it for something completely spontaneous that nobody would have been able to see coming? Like, could you have a Dejavu for an object falling off a table, and predict that the object is going to hit the ground, or could you, with no other clues it would happen, predict that the table was going to collapse purely because you saw it in Dejavu.
If you can really predict the future with this then it needs to be studied, but I doubt that's what's going on. It could also just be that you remember predicting it before it happened, but you really didn't. That's part of what's so screwy with Dejavu. Have you actually been able to tell someone before, or does it just feel like you could have?