after battery replacement find my friends fails

A few weeks ago the battery of my iPhoneX failed (it went thick and pushed the screen out), I had it replaced by a certified replacement store.

After this replacement it appears that my friends cannot see my location anymore and even sometimes my location standardly moves to a place in the lake about 5 km’s from my home.

When I open the app “Find my”, my location suddenly appears to be available again for my friends. Leaving the app stops the updating of my location.

When I use my iPad for finding my “device”, this works under all circumstances and flawlessly.

Anyone an idea how this can be caused?

Thanks

Jim