Hey Robert.
I used to work with a Panasonic HMR recorder at UNC Charlotte, hell of a great box, doing long recordings like that but at 720p60. The HMC 150 is still built off the idea of (X) number of gigs limit, which is a pain for the few frames you lose when it turns over to the next clip. The turnover was at about the same 23 minute mark. If the change in recording is noticeable, I would sometimes apply a very slight one-two frame dissolve to make it work. Occasionally the HMC 150 would have a hiccup, which one significant conclusion drawn was that the cards needed to be regularly reformatted before being used again. The 29 frame drop may come from that.
Are your renders from Vegas creating individual clips?