Game's sound turns of in Seeds of Time Map. (Garden Warfare 2)

Whenever I play the map Seeds of Time, in the Zgypt level my sound turns of and makes this muffled noise when I window it, it also does this at the end (If I prevent Zgypt from doing it). It also does it on time park sometimes and I think the map zomburbia or something when you ruin the party. The only way I know to get rid of it is to close and reopen the game. Please help me fix this, or if it is a glitch please fix it, it really takes a lot of the fun out when you have to constantly worry about it happening on these maps.