Android 8 'Oreo' bug can cause large amounts of mobile data use
Android 8 'Oreo' was released on the 21st of August and has had a smooth and uneventful last couple of weeks. However, Reddit user, Unusual_Sauce, posted a PSA recently warning others about a bug which causes Oreo to ignore wifi and use the mobile network by default. “After updating to Oreo last night, I received a huge spike in data usage, all the while being connected to WiFi. I contacted support and was told that they are aware of the issue and are working on a fix. In the meantime I have turned off mobile data while at home, so only WiFi is being used.”
Android's standard behavior, when the user has both mobile data and WiFi enabled, is for the phone to default to using the WiFi when connected to a known network, but to switch to mobile data when out of range of the WiFi. It is this procedure which is being ignored by the operating system, causing users to deplete their data cap unknowingly.
Google is aware of the issue and is working on a fix, but for those with Android 8 'Oreo,' the safest option in the meantime is always to switch off mobile data when connected to a WiFi network.