I would say it was not using your location, at least it isn’t working here in Free. I just geo-located a model in SketchUp Pro and then in Shadows, set the date to today. The Time slider goes from 04:42AM to 09:34PM and that seems reasonable compared to what’s happening outside here. I also looked up https://www.timeanddate.com/sun/ for where I live. From that site, today’s daylight is 04:35 to 21:44 (17:09 hours) which is quite similar to SketchUp Pro’s geolocated Shadow time slider.
Now in Free, time in shadows is 4:40AM to 7:16PM. The sunrise is good, but the sunset is about 150 minutes out. It won’t be dark here at that time, if it keeps going like it is now, the sun will still be shining. I don’t have Shop, so maybe there’s a setting to let you locate your model? It isn’t happening automatically in Free.