Oh, I guess I should clarify that those aren’t my typical render settings. Usually I just have it set to a constant 14Mbps. I only had the variable set to 8Mbps because I was seeing how it would look at that bitrate, but Vegas didn’t offer 8Mbps as an option for constant bitrate. The only way for me to get 8 was to manually go into variable and just set both of them to 8. I have no idea what two-pass does so that was selected just to see if it helped, which it didn’t, because of what you explained.
I’ll try using the variable 8 to 16, along with your suggestions in the last paragraph, and see how that works out.