The same happened to my XA2 Ultra dual sim (sfos 18.104.22.168) about four weeks ago. I think there were no updates between gps working and not working. I tried to give it a proper chance and left my phone outside for thirty minutes and it did not get a fix. Hello GPS! and GPSinfo showed no satellites when testing another time.
Edit: gps worked fine for several weeks under sfos 22.214.171.124
Edit 2: reboot does not help