Well this looks interesting I guess! According to a massive amount of iPhone X and iPhone 8 users during the past couple (cold) days there seems to be an issue with the LED in those aforementioned devices.
According to their reports, the camera flash doesn’t work in cold conditions, although flashlight itself works when turned on separately. And NO there’s no need to bring up the 0º-35º C / (32º-95º F) limit, as we’re specifically talking about the over-0-degree-Celsius conditions here.
The issue isn’t something new, as several hundreds of users have been complaining about the problem since months now and Apple – in some cases- offered replacement devices but nothing significant in numbers. So far there are a lot of people talking about it on other platforms like Reddit and Twitter reporting the same issue: