There are several parallel universes arguments, and these conflated memories I think many of us have (I do) are reality in another one. Another is, we are in a computer rendered virtual reality, and these are the glitches. I think the answer is simply we humans tend to conflate memories, and fill in gaps, with mixture of real memories. This is why eyewitness testimony is crappy evidence compared to measuring devices, like cameras that can capture event data.
I've been reading the supplement papers from some international conferences on Free Will.
It seems when a person is wired up to FMRI, and other electronics that can monitor real time brain activity, indicates that most people when offered choices to decide on, will push a button when they make up their mind. There is strong, convincing evidence that indicates a person's brain makes a decision in micro seconds, as opposed to when the subject "felt" that they made a decision. This has strong legal implications because the evidence suggests we are NOT in control of our bodes like we feel.