If you render to a file called fred.mp4, and the next day render again to a file called fred.mp4, Vegas asks if you want to overwrite the file, answer Yes, and the resulting file has the date/time stamp from the previous day!
The date/time Metadata comes from Windows, not Vegas.
A file overwritten with the same name will show the same creation date, with a newer modification date. Been that way since Windows 95a, more than twenty years...
I don't agree. It all depends on how the file is created!
Vegas does it completely wrongly.
No programmer should be creating a NEW file like this. Once you offer the warning that the file already exists, and get a Y reply, you need to DELETE the existing file and open a new one (of the same name).
That is how it has been done since the earliest days of computers that had a file system, which (in terms of my own OS usage) is CPM2.2 in c. 1980 :)
Overwriting an existing file is completely meaningless, not least because as soon as you have written the first few bytes the original file (which could be many GB) is corrupted and completely useless.
OK Peter suit yourself.