Hi Steve,
Yes reinstalling is the option i’m seriously considering right now. I’m using a progam I’ve used for years called Pavtube HD Video Convertor for this and it’s served me well before with getting videos into the correct format for Sibelius and Cubase. I also attempted re-rendering the video from inside Sony Vegas 14 to see if I had any more luck there.
I can certainly get the video properties box up and that’s looks fine to my eyes (aside from the fps discrepancy):
I do have Dorico installed on my main machine as well so I’ll see if I get the same behaviour there.