Sonitus Gate messed up when rendering to WAV

I have a recording where I use a volume envelope on the vocal track (see image).

 
This plays perfectly in real time under SPLAT.  But when I render to a WAV, the vocal cuts out a few seconds early, as if the whole envelope is shifted to the left. I have never seen such behavior before.
 
I reverted to 2016.12 to see if it is a bug introduced at 2017.1. That was just as goofy.  There are times when the real-time playback no longer works correctly.  The fader moves exactly as expected with the automation, but the track is completely muted. Then if I jump elsewhere in the track, it plays normally. Then if I jump back to the problem ares, it is now playing normally.
 
I have done heavy editing on this some, as it was a live recording needing some help.  I have used Melodyne several places on other tracks.  And I spliced several words into the vocal track that were muffed in the live performance.  After I did Melodyne on the horn tracks, I got some weirdness and the only way out was to close the horn tracks without events or clips (but preserving the effects chains.  Then I coped the audio back in from the AUDIO folder.  That cleared up the problems on the horn tracks.
 
I tried that same technique on the vocal track and I was still left with goofy results.  For example, after a solo break, I bring the vocal faders back up:

When I play back under Sonar, the faders go up, but the vocal is silent. Deleting envelope nodes doesn't help. If I delete the entire envelope, then the track plays.  Something is seriously fouled up here.  I tried copying in the envelope from a track I had cloned for testing purposes.  That resulted in the same problem. I guess I will have to rebuild that entire envelope from scratch.

After doing all of the above:
 1) Reverting to 2016.12
 2) Bouncing all of the edited clips to make a single clip per track with no splits
 3) Cloning my vocal track to a whole new track that had none of the clips or events, just the effects stack, and then dragging in the audio
 4) Creating a whole new automation envelope from scratch
 
it played correctly in real time under SPLAT.  But then I was back to exactly the same problem I originally had, from the first picture above.  Where I pull down the fader after the first vocal section, the vocal track disappears a few seconds too early in the WAV file.  GRRRRRRR.
 
There are serious problems here.  The WAV file should match what you hear in real time playback.
 
I note two other things that might contribute to the problem:
 
a) My clips all start around "measure 8". This was a live recording that bears no relationship to the SONAR measures, and the automation envelope should not depend on the starting point.
b) I did extend the start and end times on the ruler by a few seconds to make sure I didn't have residual garbage in the front and to make sure I got the full tail at the end.  Again, that "should" not affect the envelope, but I guess I will have to test both of those conditions now.
 
If I bounce everything (entire mix) to a new track, I get exactly the same problem as in the WAV -- the vocal cuts out early.
 
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On edit, I moved all the clips completely to the left (measure 0).  The real time playback continues to be perfect and the exported WAV continues to have the vocal cut out about 3 seconds early.

There seems to be some issue with the Sonitus Gate.  I had this gate on the vocal track, but it is not needed when I have the envelope because I can just zero the faders in the sections where I wanted to gate the vocal. On my first test at least without the gate, the vocal is no longer cutting out early.
 
I don't understand this because when you watch the gate in real time playback, it is not attenuating early -- and that is exactly as expected because the singer is still singing.  But for some reason when exporting to WAV (or bouncing) the gate is deciding that it should attenuate early.