Sudden stops in Logic when a new track starts playing

This problem has dogged me for years, with three different Macs, loads of different OS versions, loads of different interfaces and loads of different Logic Pro versions. I have upgraded from 7 to 8 and it's still happening, in fact worse in 8 than in 7: A song will occasionally just suddenly stop, usually exactly where a track starts. So for example if I have a track with data starting at bar 17, Logic sometimes, randomly, simply stops when it reaches bar 17. The track can be Audio recording, or midi playing a Logic or AU virtual instrument - makes no difference. If I reset to the beginning and start again it will always play past the problem point no trouble, every single time. Occasionally though it will stop later in the song where another track starts. It makes no difference how much processing is going on. I have songs with only four bounced (not frozen) audio tracks and a bit of external midi, where the CPU bars on my Macbook Pro don't even move, and yet it can stop, not always, but sometimes. I use Logic Pro live on stage and it's a killer I can tell you. Anyone else suffering the same problem? I'm thinking of abandoning Logic and going to Ableton!