iOS 9 battery draining issue: background App Store activity

[notcome]

Today my iPhone 6s ’ s battery drained very quickly. In around 5 hours it gets to around 20%, during which period I was taking 3 50-minute courses. I noticed that it showed App Store consumed 40% power, only 1 minute foreground activity but 4.2 hour background activity. Then, I enabled the Low Power mode to make it survive the next four hours.

When I finally got home and charged it, I noticed that App Store ’ s background activity time has increased to 7 hours. I didn't enable auto update, which should be disabled in Low Power mode automatically anyway. So, I believe this is a bug. I have just restarted it, but not sure if this will work. Anyone with similar issue?

iOS 9.0.2, iPhone 6s

直接拷贝懒的翻译了，然后 @livid V2EX 的字体回退设置有问题，中文盖到英文的前面了，所以「‘’」显示成一个汉字的宽度了（不要告诉我这是故意的——很有道理，毕竟除了少数强迫症大家都用「'」）