Boris scrolling title glitch

I''ve created a 3.5 minute scrolling title using Boris titles in FCP 5.1.4 There is a stubborn glitch in the scroll where every 15 seconds or so the scroll will jump ahead very slightly (1-2 frames). What's more, the jump does not seem to occur in the same place each time. All titles are fully rendered. I've tried using different fonts, changing the scratch disc and pasting the title into a new timeline in a new project. The glitch persists.