From the way you’ve written your post, I get the impression you are using the supplied burning engine - the VSO one - and are experiencing your problems with that engine.
Although touted as “updated” in the new release of DVDFab, I suspect that it is a little ‘buggy’, as there have been several reports of problems from people using it.
Since the DVDFab authors didn’t write that burn engine, they can’t fix it, either. We’ll have to wait until it is updated again, and hopefully, most of the bugs will be removed.
I’ve been monitoring the VSO forum to see what sort of problems those people are seeing, and few comments have come close to what is being reported here.
I know Fengtao and Ting monitor this forum, and I imagine our concerns are being forwarded to the VSO people, so hopefully there will be a less buggy ‘update’ soon.