Greetings, Nattie30.nf
I see that you're wondering why a friend's location changes drastically while using the Find My Friends application on your iPhone 8 Plus. I'm happy to help.
About privacy and Location Services in iOS 8 and later -- Review the information below.
With your permission, Location Services allows apps and websites (including Maps, Camera, Weather, and other apps) to use information from cellular1, Wi-Fi2, Global Positioning System (GPS)3 networks, and Bluetooth4 to determine your approximate location5.
Apps that can show your location on the screen, including Maps, show your current (approximate) location using a blue marker. If your location can't be determined precisely, you'll see a blue circle around the marker. The size of the circle shows how precisely your location can be determined—the smaller the circle, the greater the precision.
When Location Services is active, a black or white arrow icon appears in the status bar.
Maps, directions, and location-based apps depend on data services. These data services are subject to change and might not be available in all geographic areas, resulting in maps, directions, or location-based information that might be unavailable, inaccurate, or incomplete. Compare the information provided on the device to your surroundings and defer to posted signs to resolve any discrepancies.
Learn more about how Apple and third-party apps use Location Services.
Get help using Find My Friends -- You came to Apple Support Communities from this article and it contains the explanation you're looking for. The information regarding your friend's location was updated.
You might not see a device's current location if it needs to update in iCloud. Wait a few minutes, then try again.
If you're signed in to Find My Friends on more than one device, you might need to check which of your devices your friends can see:
- On an iPhone or iPod touch, tap Me, then tap your active device under Share My Location From. This choice only appears when you're currently signed in to Find My Friends on multiple devices.
- On an iPad, tap the List button, tap Me, tap Info, then tap your active device under Share My Location From. This choice only appears when you're currently signed in to Find My Friends on multiple devices.
- On an Apple Watch that uses watchOS 4, press the Digital Crown to see the Settings icon. Choose Settings > General > Location Services. Make sure that Location Services and Share My Location are turned on.
Take care!