Your response is quite negative and I was trying to get away from Adobe. Maybe I shouldn't. It was an avi but I certainly don't know condecs so I guess Vegas has audio limitations.
There is a known issue if the audio inside the AVI is PCM 24 bit.
Former user
wrote on 5/4/2020, 4:12 PM
You have to demux the 24bit audio from the video. Then you can import the audio into Vegas. Vegas does not like an AVI with 24bit audio. I use Virtualdub to demux.