Whenever I travel to the western side of South Dakota, my phone (Galaxy S8 on Sprint) almost always reports the time as central time. Western SD is in the mountain time zone, about 125 miles from the nearest central TZ line. Sprint does not have a presence in that part of SD (indeed, their network covers only about 2.5% of SD), so I am most often on roaming. Phones for people who live there are fine, so it’s not a tower issue, per se. Of course, they aren’t on Sprint, either.
about 5% of the time it shows correctly as mountain time, the rest it shows central. I can’t rely on my phone for an alarm or for getting to meetings. What could cause this?