I have same problem. my and my wife’s iPhone. I’m not 100% sure, but it seems that the problems started after the update to ios 18. What is 100%, when the problem appears, it is always at the moment when the phone is connected to Apple CarPlay.
There is no problem tracking the GPS position on the phone - the location history in the Home Assistant app is still updated. Sending the location from the app to the HA server is interrupted (for remote connection we use Nabu Casa).