ZwiftPower finish time different than Zwift Companion app

I raced yesterday in STAGE 4: COBBLE CRUSHER - CASSE PATTES (zwiftpower event zid=3620396 ; sorry, full link not allowed). ZwiftPower shows my finish time as 50:36 (scroll down to last finisher). However, the Zwift Companion app (the overview page with the route map) shows my time as 50:20. Why the difference?

Edit: Zwift Companion “Race results” shows 50:36.1 which agrees with ZwiftPower.

Thanks,
Don Culp

It’s to do with your time in the pen before the start line. It’s always been an issue. As a runner it totally messes up your average running pace as you can gain up to 30 seconds on your time.

Quite a lot if you’re going for a PB