I've not had this issue. I'd try restart device, and if not, try a mobile network reset: settings -> system -> reset

Is there an alert of an error / crash log?

 

 Restart works BTW. But reset mobile network and WiFi doesn't do anything  

 Appears to be a known Android 15 issue that's looked into. Most reports say it's not been happening for a while though. 

 Word. I've had little issues lately but for a but it was pretty consistent. Thanks for the update.