Why does iPhone X keep changing my manual time setting to set automatically?

Settings > Privacy > Location Services > System Services > Setting Time Zone. Turn off. Just had to do this to my iPhone X, I’m a truck driver and must stay in EST

My new 7 Plus is going the same thing and I’m very frustrated. I travel between Eastern and Central time zones often but prefer my phone to stay on Eastern. It’s never been a problem with previous phones.

I have the same issue and have reported to Apple tech consultant. It's been almost two months and they still can't help me to solve the problem yet. And it's not just one phone, it applies to all iPhone x I think. You can set your time manually, but once you restart the phone, it just goes back to set automatically without any reason. So frustrated about this issue.

Did the same thing, but after powering down for a long haul flight, it's still resetting to the local time zone when I land in the new destination. Observing GMT-8, but residing in GMT+5. I want this feature turned off.

Yes pretty annoying! If I restart or update my phone, the time settings reset to automatic. I live on the border of two different time zones. I live in one and work in the other. If my phone restarts, everything goes an hour behind my work time zone and throws off my alarms to wake up. Pretty annoying.

I did as per your suggestion but still my iphone x switches back to automatic date & time setting after reboot.

Thank you for your hint. That solved the issue for me.

The annoying thing about that is, that even at apple (genius-bar) no one was able to assist me and provide a solution.

Same here. I have the same problem.