Ok, I've been having problems with premiere cs6 loosing playback sync. I run a very fast machine with a raid Zero project drive and a Black Magic Declink card.
When the timeline plays out of sync (doesn't show frames out of sync) I exit and reload Premiere and the sync is correct.
Lately, I've found that when playback goes out of sync, if I go into preferences and change the default device to Premiere Pro WDM Sound the timeline is back in sync. However, if it goes out of sync with this setting selected, I can go back to the Default audio device and change it back to Black Magic audio and WHAM, the timeline now plays back in sync. WTF!
This is happening when I import AE lower third graphics lately, but there have been plenty of instances of this where no AE import was involved.