Apple has decided to disable one of the features of the Health application, specifically the blood glucose tracking capability, until it can issue a fix for issues reported by users in the UK and Australia, CNET reported tonight. The feature will apparently be removed through an incoming software update (perhaps iOS 8.1, or possibly 8.0.3) while the company prepares a patch to remedy the problem. Apple has also provided a longer explanation on its support website:

While it’s true that the HealthKit framework supports measurement standards for both the United States and abroad, a bug that exists in the current version prevents users from manually entering or viewing blood glucose levels using anything other than United States measurements (mg/dL, or milligrams per deciliter) within the actual Health application. The UK and Australian standard is the millimole per litre (mmol/L).

HealthKit supports both units of measurement. However, if you measure your blood glucose using a device that displays mmol/L, those values can’t be manually entered or displayed in the Health app with that unit of measurement.

To prevent confusion in countries where mmol/L is commonly used, we’ll soon release a software update that will temporarily remove the ability to manually enter and view blood glucose values in the Health app while we work on an update to support both units of measurement.

If you have previously entered values manually in the Health app, you’ll no longer see this data in the Health app after the update. However, your data won’t be deleted, and other apps with permission to read health data will still have access to blood glucose values that you previously entered.

Third-party apps will continue to be able to support both units of measurement and can continue to use HealthKit APIs to store blood glucose data.

Apple issued a statement on the problem, saying:

Apple also informed CNET that following the update, users will no longer be able to see blood glucose levels in the Health app, but the data will not be deleted permanently. Once the fix has been released, the old data will appear in the correct format. Third-party apps will still be able to input and access this data even after the update removes it from the main Health app, providing users with a way to view this critical information in the meantime.

This isn’t the first time Apple has experienced a major issue with the Health software. When iOS 8 initially launched to the public, all third-party apps were suddenly barred from using the HealthKit framework while an issue was investigated. The 8.0.1 update re-enabled the capability, but introduced a whole separate set of issues.