https://bugs.winehq.org/show_bug.cgi?id=50001
--- Comment #1 from Andrew Eikum aeikum@codeweavers.com --- Thanks for reporting.
I think this is actually a side-effect of Bug 49839. The steamwebhelper process continually crashes, which takes up a lot of server time for one reason or another. Occasionally the audio thread gets caught up while the server is handling the crashing processes, and so the audio output gets interrupted.
I'm able to reproduce the problem with plain Wine with Windows Steam. With wine-staging, the steamwebhelper crashes seem not to happen, which fixes the game audio for me.
Are you running the game via the Windows Steam client? Are you using wine-staging, or just plain upstream Wine?