You may want to check out my sound issue. https://answers.unrealengine.com/questions/539666/concurrency-broken-in-414.html
Mine feels more like if alot of spamming sounds have played or are playing that the sounds break. As this not only happens when paused but in the normal game itself. My repro case does include pausing however. But the issue I found is because so many sounds are playing, it tries to play the sound, even giving it a volume of 1.3 (as designed). But isn’t actually audible.