A newly-discovered Android Oreo bug could be causing some phones to use mobile data even when the device is connected to Wi-Fi. For users with limited data plans, this could cause serious problems.

The bug came to light on Tuesday, when Reddit user Unusual_Sauce posted a PSA about the issue. Other users claimed to have experienced the problem as well, while some posited that it could simply be a settings issue.

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The full Reddit post reads:

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.

The good thing, if the post is accurate, is that Google has been alerted to the issue and is working on a fix. The reason for the issue seems to be a little harder to pin down.

As pointed out by Reddit user evan1123, Google seemed to have changed the default setting for its Mobile Data Always Active feature to “on.” The default setting for this feature traditionally was “off,” but Google could have changed it with Oreo, or simply forgotten to the set the default to “off” before its release, as Redditor purakushi pointed out in the comments.

If Android users running Oreo are concerned that they might be experiencing this issue, they should check the Developer Options in their settings and disable the Mobile Data Always Active feature if it isn’t already. That is, until Google delivers an update that addresses the problem.

While the issue may seem like a big deal, it will only affect a very small percentage of Android users. As ZDNet’s Liam Tung pointed out, Oreo is currently only available to select Nexus and Pixel devices. Still, any concerned users should check their mobile data usage to make sure that they aren’t going over their limit.

Google has also been working on some potential Bluetooth issues in Android Oreo on Nexus and Pixel devices as well.

At the time of publication, Google had not responded to a request for comment.

The 3 big takeaways for TechRepublic readers

  1. Android Oreo could be causing some smartphones to use mobile data even when connected to Wi-Fi, according to a Reddit post from Unusual_Sauce.
  2. The culprit could be the Mobile Data Always Active feature, which is typically set to “off” as default, but could have been turned on in Android Oreo.
  3. Android Oreo users should check their mobile data usage, and check the Developer Options in their settings to see if they are affected.