But with a caveat; I was rendering an entire 1hr film which is WIP and 30 minutes in the center of this was all made in Vegas 18 during which I had to back then endure the bugger. I did take precautions to empty the redo bin before I had begun the rendering but I had not closed down Vegas based on the evident bug free performance of V 19 so far. The scenes that open the first 15 minutes and the last 15 minutes were all edited in V 19 and no black frames appeared in those two sequences. So could this be that black frame bugs are remnants of V 18 and that this experience only proves that 19 is as good as gold? Right now I am re-rendering after first having completely powered off and restarted my computer.

EDIT:

After closing down computer and restarting there are no black clips. But I am interested to hear whether what happened earlier means that one can expect observing black frames or clips when rendering in v19 projects edited in V18. Does this make techie sense at all?