Occurred as soon as I imported the files and put them onto the timeline. Only lasts for a few seconds but the source video is fine. This is an example of what results:
Your source video may not be "fine" for editing. Unfortunately, playability often does not reveal transport stream errors. We need to look at the source properties to see if that is likely.
That's why, because they are transport streams from a capture utility. . I'll give you the long answer later, after you've used Quickstream Fix in Videoredo trial version. See how many bad frames it rescues or drops, and report back.
add: I only recording Vegas Pro's activity, not the games (since I rarely playing games), and so far so good... The settings are default too. Perhaps I will need to try experiment with games. Can't promise when... currently my computer system is being used to long-render my project...