I have the same issue, I believe. My car is a Volkswagen TCross 2024 with Carplay. My phone is a iPhone 13 Pro Max 128gb. Before updating to iOS 18, everything was working fine with the GPS based apps such as Waze, Google Maps and Apple Maps. The navigation was fluid and I had no issues at all. After the iOS 18 update, all the GPS apps have an issue that is it seems that the map is "jumping around" while driving. Sometimes it jumps to a place that I'm not at and the navigation becomes confusing and unsafe. After a few seconds, my position is acquired back and the map shows the correct position. Apple Maps, Waze and Google Maps at their latest version. Yesterday I did a iOS rollback to version 17.7 and tried again all the GPS navigation apps at Carplay and it seems to be fixed, the maps aren't jumping around in this version.