Playback cutting out

Since changing from MS3 to MS4 I've found that the playback on a score can occasionally drop out at random. I can't pin down a reason and there seems to be no pattern or consistency. It will suddenly go silent for a few bars on playthrough but if it's a repeated line the repeat may play without interruption. I'll attach a file where it's happening (though S*d's Law may apply, and it works fine for someone else). Can anyone explain or advise?