For some time now, Zwift has not been recording my PBs in the London and New York worlds (and perhaps others). The PB will be registered during the ride itself, complete with confetti & leaderboard, but there will be no record of it in the companion app.
This happened to me again yesterday in New York. I have not ridden the New York KOM since February, so any time would have been a 90 day PB for me. I get to the top and sure enough – confetti & a brief flash of my final time. Checked the app later to confirm my memory of the exact time, and no PB shown.
I have not determined whether or not this effects HoloReplay in these worlds also, but I suspect that it does. PBs work normally for me in Watopia, BTW, as does HoloReplay.
I don’t have Strava, so can’t doublecheck PBs there & must rely on the app for this info. I run Zwift on Apple TV.