I'm not sure if anyone is experiencing this but it happens to me all the time and it's so so annoying.
When playingback the timeline on CS6 the audio cuts out at random places and then it comes back, then it goes again for a few seconds then back again,..while video keeps on playing.....this is just random and it can happen as soon as you press play or after a few seconds and it happens when audio is stereo, mono, mp3,wav,aif, you name it.
Also, it happens regardless of playback quality or timeline render status (red, yellow or green). My computer is quite fast + 24gb RAM so I dont think the PC is a problem, It also happens on a different computer within our studio.
Needless to say that editing under these circumstances is becoming impossible/frustrating and I'm even considering finding other software to edit with! I've found others with this same problem at cretive cow http://forums.creativecow.net/thread/3/935424