Ah yes sorry, that ActiveAe syncstream error was just me trying to decipher the logfile with very limited knowledge. I thought that error had to do with the stutters but it was just a suggestion. But I had no issues with audio sync or whatever. The audio stays sync all the time. It just stutters sometimes.
Thanks for the suggestion. I will try disabling TrueHD passthrough tomorrow. But as I said, the issue also occurs if I set the the audio to a low bitrate ac3 5.1 track.