[tz] Anecdotal discrepancy for Navajo nation in Arizona

Hi, A colleague recently visited Page, Arizona, and the Navajo reservation right next to it. His phone must have been associated with a cell tower inside the Navajo nation, because his zone was set by NITZ to America/Denver (DST in effect). This matches the current TZ database. However, he observed that the parts of the Navajo nation adjacent to Page were actually observing the same time zone as Page (America/Phoenix, DST not in effect). I wouldn’t make any changes based on this one anecdote, but it might be worth checking if anyone has any sources inside the Navajo nation. Thanks, Debbie