That was basically my situation with gunshots causing music to cut out. I struggled with it for awhile and never did find a solution of my own.
4.20 definitely seemed to make it better, using the checkbox on the sound asset. But it is still present, albeit not quite as pronounced.
I understand how you feel about updating. The 4.20 update went pretty smoothly for me, but you never know what might break with your specific project. 4.18 was a very solid release I had almost zero issues with.