Goofy issue here - not sure if related with vox, but it is sound related...
Sometimes when taking a nasty death - one where the pings and noise are still coming in after you're n tower....OR sometimes when starting a mission....
Upon the next reupping of a plane(or up of mission plane) , there will be no engine sound. It'll kick in later - maybe 20 seconds to several minutes after.
It does play the enigne start sequence to the normal engine sound. You can hear external sounds and vox - just no engine.