We’re looking into this and hope to have a fix in place soon.
The company responded after a Medium post by product developer Matt Galligan, who noted that the app was continuing to draw significant amounts of power despite having background app refresh disabled. Others then chipped in on the issue, prompting Facebook’s response.
It had been suggested that the high battery drain might be due to the Facebook app continuing to use Location Services in the background, but the company told Motherboard‘s Jordan Pearson that this is not the case.
A Facebook spokesperson emailed over the weekend to say that the battery drain issue “is not caused by improper background location collection,” and that the team continues to investigate the issue. “We are not collecting background location on iOS unless Location Access is set to Always on your device and you have enabled Location History in the Facebook app.”
On my girlfriend’s iPhone, for instance, iOS 9 reports 5 hours of on-screen usage for the last 7 days, and another 11 hours of background audio usage with Background App Refresh turned off.
My guess is that Facebook is hijacking audio sessions on iOS by keeping silent audio in the background whenever a video plays in the app.
Facebook has not commented, beyond its confirmation that Location Services are not the culprit. The company recently updated the app to support 3D Touch Quick Actions for status updates and photos on the iPhone 6s/Plus.