SO when I had the old Gear Vr with my S7 I had this issue and now that I got my s8 and a new Gear Vr I am having the same issue:
When I am using certain audio things such as the game CELL or that BEAR VR thing the part where people are talking gets very very choppy.
When I use my Gear VR I use my Beats headphones and put phone on airplane mode.
Things I have done to try and fix the issue:
Turned off WIFI
Used the Gears built in sound
None of the above work.