Hello @Peter_Gintz welcome to Zwift forums.
The sprint bug in Yumezi / Makuri Islands as fixed with game version 1.15.0, which officially released 30 minutes ago. Please update to the latest version. The one that went out to some players on Friday was a mistake.
If anyone is still experiencing this bug - especially for the mobile OS’s (iOS / Android / Apple TV) please go to your respective app store and check that you are on the latest version.