Location tracking updated without remote URL

I’m having a weird issue and am somewhat confused with the location tracking feature. Some days ago I activated the trial of HA Cloud, after making a fresh install on a RPI4. I installed the mobile app on my phone and used the internal IP as URL.
Today I am at work and logged in to my HA via remote access. And it showed the location of my phone - although my phone shouldn’t be able to contact my HA. Or am I wrong?

Here’s my config of the mobile app: