Well, this isn't good.

Just hours before it is expected to release its new iOS 8 mobile operating system, Apple is reportedly facing problems with HealthKit, according to MacRumors.

HealthKit is a service that will allow fitness apps to interact with and feed information into Apple's new Health app, which will track a user's heart rate, calories burned, and other fitness-related metrics.

The issue is so severe that Apple has even pulled HealthKit-compatible apps from the App Store, according to Carrot developer Brian Mueller.

Update: Apple has just confirmed that a fix for HealthKit will be available by the end of the month, according to Financial Times reporter Tim Bradshaw.