Im trying to render a video on WMV 11, with custom settings that can be found here and the video on the timeline looks good but when i render looks like THISTHIS, at the end of the gif you can see that the colors looks weird. I also rendered a
with this settings to show how it looks. I also uploaded the raw video with no render in case someone wants to see how it is supposed to look like
I cannot help with Vegas Pro 15 since I do not have that version but are you able to reproduce this with say Vegas Pro 13 or below? That at least would tell you if you have an issue with the Software or the WMV 11 codecs.
I seem to remember that the .wmv codec was not too happy about rendering in custom image sizes. We had problems with that at work. Did you try rendering the video in one of the preselected options? I would give that a try as a test. I know it won't look the same as your custom settings but it might help you determine what is going on. If you want to create a custom image size you might have to pick a different codec. I hope this helps you.