Google has just run into a big stumbling block with the Android 5.0 Lollipop update. According to reports, the OTA updates for the Nexus devices have been delayed because of a WiFi bug in Android 5.0 that is draining the battery of the devices.
Android 5.0 Lollipop had started rolling out to devices some days ago, but it seems that the updates have been stopped because of this issue. The Nexus 4, Nexus 5, Nexus 7 (2012 and 2013) and Nexus 10 will be the first devices to get the update. Google has itself confirmed the bug on its Bug Tracker page as well.
Users ran into the issue on the Nexus 5 first and the Bug Tracker page is filled with queries about the same. That said, it's not yet confirmed whether the WiFi tracking bug is the cause for the battery drain, but both the bug and the issue exist in Lollipop.
Google had said in its I/O conference back in June that the Lollipop update would bring better battery life to Android smartphones, along with the battery saver feature. Many smartphone makers have already confirmed the update on their various devices, but the discovery of this bug may delay their plans as well.
Source: Android Police