Here's one that I just discovered. When going from "Best (auto)" preview to "Preview (auto)" the selected video track goes black and for just the frame you were on at the time it stays black until you exit vegas and reopen the veg. It's just as though vegas blacked out that one frame. I can render to ram and the black blip is still there. Very strange and repeatable. It happens while working with an HDV 1080 60i project, never noticed it on SD. Have not tried to render to see if the black frame shows up.
Anyone else discover this?