Google Reveals Culprit For Android Battery Drain Bug Following Its May Update
This is precisely the reason why a recent mystery juice-draining event was taking place across a portion of the Android handset world. It turns out that the culprit was some poor coding on behalf of the Instagram app, The interesting bit of this is that the problem was widespread enough to garner attention from Google itself, as it posted a very plain page on its Community help website, asking users to update Instagram to the latest version.

The page doesn't offer any other details, particularly about the actual root cause (if there is one) or whether the affected devices are only its own Pixel handsets or Android phones at large. Having said that, according to 9to5Google, the company responded to complaints about mysterious battery drain on Pixel devices following the latest May system update pointing the website to the support page linked above.
In order to update Instagram and any other apps to their latest versions on your Android phone, go to the Play Store app, tap your profile icon, tap "Manage apps & device", and the second item in the list will show how many apps need updating and offer an option to do so right away, usually "Update all." Even if your particular phone isn't affected by this, better safe than sorry.