I have an iPhone 6s 128 GB on iOS 10.3.3. I've noticed that for the past week or so, the official YouTube app drains the battery really quickly while watching a video. The phone also warms/heats up while watching a video when previously I never noticed an increase in temperature while watching videos. I haven't changed anything and the YouTube app is always up-to-date. I do remember one thing though. Just before this started happening, the YouTube app crashed when switching from the subscriptions list tab to the home tab. This is the first crash I've gotten with the YouTube app. After that crash, it seems it drains the battery real quick and heats up the phone when watching videos. I've tried deleting the app and reinstalling it and it made no difference. Any ideas? Just to give you an idea, I was just watching an 11 minute video and the battery went from 67% to 61% by the end of the video.