This is not an x2 related issue, this happens with X1 too. 
 So a little more detail , if I have a project that has a bunch of tracks , fairly complicated , if I have the browser open and I audition loops while in play back, I will still hear certain tracks go out of sync , Now if I stop play back and hit play again , I will still hear something out of sync , now if I hit stop and close the browser , then hit play , Everything is fine .. I did notice this in x1 and now in X2  .
 I had sent a bug report in around Febuary , which I recieve an email that said something like this issue is closed . :( 
 My question is has anyone else seen this behavior . And Is this being investigated  .. Thanks. John