I’m really curious as to why this file would be a problem in Vegas Pro. Would you share the actual file on a cloud share and post the link here (or message me privately)?
I was successful in getting the audio and video into Vegas Pro.
Before I show you any of the 97 different ways to do it, I'll tell you why I think you have the problem.
SWAG
I think the video clip is a portion of the many files from a DVD that were divided in to 1GiB segments in order to be written on to the DVD Media.
/SWAG
Action
If you still have the DVD that the file(s) came from, copy all of the contents into a folder on a hard drive in your system and use a DOS command to recombine the files into one file.