I have Real Racing 3 installed on my s7 edge. Got the same sound issue. But I no more use the game launcher & always close all background apps which seems to have solved the problem. Give it a try & let me know
Thank you Tucker for yr help. After rebooting the phone the sound was back, but after some hrs the same problem happen. I also reinstall the OS, and that reduces the frequency.
Hope a new update from Samsung will solve this problem.