https://techcrunch.com/2017/11/16/apple-releases-ios-11-1-2-to-fix-iphone-x-cold-weather-issue/

Apple has made iOS 11.1.2 available, the second minor point release it’s put out in as many weeks. This one is specifically designed to address a bug where the iPhone X could become temporarily unresponsive to touch input when moving from warm weather to dramatically colder temperatures – like venturing outside in winter in Canada, for instance.

The update is also said to address an issue where Live Photos and videos captured on the iPhone X might show some visual distortion. It’s available now, and should show up if you go to the update section of your phone’s Settings app.