I had this problem in both betas. There would be no sound in slapsh screen or in game. I already tried reinstalling game and reintaling the ue4.exe. Still no go. How ever i figured somthing out. I launch game then alt-Tab change my sound seeting to my head phone. Exit game. Launch game. Then sound works. Then al-tab to change it to my speackers system. Then only after i click battle and then exit to main menu. Then sound kicks on my speackers system.
After moving the battle barge throught the mine field. I got to the blue line "safe zone" The next event did not trigger. I had the barge fly all over the map.
No choas ships entered from behind. The objective did not trigger complete.
It did this twice. The thrid time it did trigger...and some really nice kabooms...followed. With repost if it happends again.