Facing battery life issues when watching videos from YouTube? I think yes. YouTube app 12.44 had a bug which caused battery drain and overheating when watching video on iPhone/iPad. But with the latest version of YouTube app v12.45 available in the AppStore has now fixed an issue with battery life & usage.
If you have disable the automatic update, Launch AppStore and go to the Update tab and Hit update to get the latest version of YouTube. and if you enabled the automatic update, it will automatically install the new version.
After updating, check it by going into Settings → Battery & confirm that your battery is running fine.