Somewhat small complaint, but this bit me. Did a half marathon and got a PR, stopped when my watch hit 13.1. Strava didn’t record this as a HM because it had the mileage at 13.09 or something. Very annoying and still irks me.
My first organized marathon I kept running after the finish line, through the crowd of stopped runners, until my watch hit 26.3mi just so I could be certain It'd show up as a PR in Strava/Garmin.