Jay's story "checked out" because it matched the cell phone evidence and also the testimony of another witness. The problem was that the cell phone evidence was later proven to be completely misinterpreted, and the other witness's testimony apparently misremembered the day (it was something along the lines of her being in class at a certain key time). Without those, it sounds like there's nothing left for his story to rest on.
We're forgetting that Jay knew the location of key evidence.
The cellphone data was only "misinterpreted" in that it was not a slam dunk, but we can still conclude they don't line up with Adnan's testimony for the day.
> witness's testimony apparently misremembered the day
... based entirely on a random interview about what another person remembered 20 years later.
