Interestingly I think that Strava might have improved their algorithm recently.
I had one of those ‘uh oh’ emails last week telling me someone had taken one of my (few) KoMs.
It’s a short 6% uphill that is preceded by a nice downhill where you can really wind up the entry speed. The current KoM time is about 50s at around 700w (me) but the ‘new’ time was 16s quicker which is pretty mental.
Anyway, by the time I’d got around to logging into my account to see the ride of the new leader, the system had already removed it from the leaderboard.
Weird - but cool. 
I’m assuming an auto-correct but I guess the rider could have potentially removed it themselves due to reclassification as an E-bike ride.