Bug: Pizzicato Not Registering After Part Export

What happens is this: I have this one song, where the violins and cellos go Pizzicato, that is, when they switch from using a bow to plucking, and when I export the whole project, it sounds just fine. However, when I export the parts of the project and put them together, the Violin and cellos don't play the pizz. passage correctly! They just play it arco, which ruins the feeling! This is strange, right?