All iPhones stopped tracking

On 13th March all the iPhones running the Home Assistant companion stopped sending (or perhaps more specifically the map stopped showing) their locations. The one device that kept working was the Android device.

I thought it might be an update I ran or a plugin I installed so I reverted to a backup taken on the 12th but still not iOS device tracking.

The companion app itself seems to be working ok and permissions have been granted and HASS can be reached locally and remotely.

Are there any known reasons why this might happen, and if theres a fix as its been working well for the past 6 weeks or so.

I can tell you why I had this issue with iPhones, might be the same.
Apparently IOS constantly asks (periodically) to renew the permission for location and the app I used kept getting switched to “When using app” instead of “Always”.
Check the location permission for the app itself and see if yours changed too.