Actually I am having same problem in my just 3 months old M31,there is no error message,not anything,it just stops working suddenly and doesn't get back untill I restart my Device and then get those features back for only 5 minutes and then it stops again and again,it happens to me whether the battery is over 70% or it us below 20%.I have checked for updates but there aren't any.I have tried my best to reach to solution but no solution has worked for me.I also contacted customer care but the solutions given by them didn't work too.I am waiting when this issue will be repaired.If anyone have any solution,please speak up because it is too irritating.
It only does that when my phone is kinda hot. I'm not really sure if the battery matters. My girlfriend who uses s9 however, doesn't have this problem. Even though it's been nearly 2 months, I still have the same problem occuring.