Hey, I have encountered 2 possible bugs with sounds.
To make sure that they are investigated, I hope it is ok to post them here, since noone answered my answerhub reports yet.
Greetings
https://answers.unrealengine.com/questions/201955/bugsound-mix-modifier-not-working-properly.html
https://answers.unrealengine.com/questions/201942/bug-editor-sound-doesnt-mute.html