I have a certain still that I am trying to get the flickering out. Every time I check or uncheck something in the properties, it crashes the project. Vegas disappears. I'm using 5.0a. Should I upgrade to 5.0b. Would it correct this bug?
First upgrade to 5.0b
Second, it may or may not fix your specific problem. In an earlier build there were some bitmap issues, but this may be unrelated.