We have been contacted by users reporting that their iPhone is telling them that they are using unexpectedly large amounts of data when using their mobile data plan while connected to Proton VPN.
We have found that the cause of this unexpected data use is an accounting issue with iOS 14. The iOS 14 operating system is counting the same data twice: once as it passes through Proton VPN and again as it is used by the end app. This, of course, is incorrect. Proton VPN itself uses minimal data. It encrypts the data that other apps use.
This double counting only occurs under specific circumstances. You must:
- Access the internet using your mobile data plan (as opposed to being connected to WiFi)
- Be connected to Proton VPN
- Use the OpenVPN VPN protocol (this issue does not occur with IKEv2)
Our research has found that this bug affects most major VPN services that use or offer VPN protocols other than IKEv2. Unfortunately, as this is an issue with how Apple’s operating system counts data usage, there is nothing we can do to fix this bug. We must wait for Apple to address it in an update.
We have already contacted Apple regarding this issue.