DV Info Net - Losing 24 minutes of audio from 53 minute video

One of my functions at church has been to videotape the Senior Minister at our Men's Thursday Morning Bible Study. This lasts almost an hour. I setup my Sony HDR-HC9 with a Rode Stereo Video Mic., set the camera from audio AGC to manual gain, and the manual gain level. The camera also gets plugged into a small external monitor. I plug my headphones either directly into the camera or into the monitor, so if there is a sound problem, I know about it. I also have the camera plugged directly into a PC laptop via FireWire for direct capture using Vegas MovieStudio 9.

This past Thursday I recorded the 54 minute event, and generated a file checksum for the video file (1080i60 m2t), which allows me to verify file integrity as it gets copied around. I then copy the two files to a USB hard drive (WD Passport 160 GB). When I get home the two files get transferred from the USB hard drive to my desktop computer for verification, edit, render, and DVD creation.

My problem is this. When I load the video file into Vegas on my desktop, Vegas does a scan of the file to build the sound waveform view, or I assume that's what it's doing. It skips over the sound from the ~2:34:07 (minutes:sec:frame) to ~26:33:14. Indeed, I can watch the scan skip from 3% to 50% in the blink of an eye. When I look at the sound track in Vegas, the sound flatlines from between the aforementioned times and when I play it to start figuring out where my chapter marks should go from the sound, the sound goes dead quiet for that ~24 minutes.

I can play the file just fine in VLC and the sound is all there!
Does anybody have any idea what's up with this?
I've done this half a dozen times so it's 100% repeatable - on my machine at least.

Thanks in advance.