I have verified that a problem I was having with lip-sync
drifting is actually caused by the fact that Vegas doesn't
apply the timestretch filter when it comes to render time
in the way one should expect.

I have an hour + twenty minute long audio file. If I use
Timestretch in vegas to shorten it by 8 frames the Timestretch
will not be applied at render time. Previews and the
timeline in the audio track will sound and look right, but
in the end, the timestretch doesn't get applied.

Checkout a screenshot of a demonstration of this problem,
http://www.pixelogix.com/~moored/timestretch.png
my veg file is at
http://www.pixelogix.com/~moored/timestretch.veg

The second audio track contains the audio event which was
shortened by 8 frames using the A03 crossfade scheme. The
audio event is normally 1:24:00.05 long. I used the "Render
To Track" feature to make track 1. You can see in the screenshot
that as of 1:26:05.05 the rendered track does not resemble
the time stretched event.

I duplicated the original track (track 2) to make track 3
and turned off the Timestretch. As you can see, track 1
is almost identical the track 3. It is as if the timestretch
was never applied. It seems that my timestretch is so small
that Vegas ignores it. This is fine, I guess, but why does
the timeline and preview lie to me?