Yes, but older version, even after confirm that, don't let render to start, because file is in use (by vegas of course). To be fair, error thrown by vegas says, that error isn't know :)

I've tested it on other fileformat, and surprise. Bug works for 'sony xavc-s' but not for 'magix avc/aac mp4'.

What you report has never happened here. 3 versions on my machine.

I'm confused. You asked the program to overwrite the existing file and it did. I've been using Vegas 13 since the day it went on sale and it has always done exactly what you asked of it: overwritten the file in question.

This is consistent with the behavior of every Windows based program I think I've ever used.

I can reproduce the behavior here with MXF, but I'm not concerned about it. You were warned.

If you consider overwrite file as right behaviour, then you must say, that there is bug, when you CAN'T overwrite file :) so, bug is bug :)