Another day, another alleged problem with iPhone 5.
Although to be fair, this one is more of an issue with iOS 6, which is the latest operating system that can run on a range of Apple devices.
The Guardian reports that a number of users have been complaining about a significant hike in their monthly bills due to a sudden increase in their mobile data usage.
It is speculated that this is due to a potential bug in how iOS 6 switches between 3G and Wi-Fi connections. It is thought that it's related to the iTunes Match service or possibly iCloud synchronisation.
Some users have reported that even if iTunes Match is set to restrict its activities to Wi-Fi only, some downloading and uploading of data is taking place over the mobile network, using large amounts of data.
The added complication, of course, is that a high number of iPhone users are on tariffs with a 500MB monthly data cap. Going over that can sometimes result in additional charges.
This is just the latest problem to plague Apple since the launch of the iPhone 5 and iOS. As well as the iOS 6 Maps debacle we've there has also been complaints about the camera and scratches on the casing.