Hi DigiTechSupt
I'm sure you don't need to see this but if it helps, I have recorded a short video with this happening several times on my system. It happened once or twice when I moved to Lion PT 9.0.5 but now it seems to happen every few minutes. Changing HW Buffer ALWAYS sorts it out (at least for a few mins).
This is the video:
http://www.vimeo.com/28191724
Paul