I can not get the pro channel automation to work consistently.  I had the vfk delay on a vocal bus track and thought that maybe it was because it was on a bus that it would only sometimes work.  So I inserted it in the prochannel on the vocal track itself and is still not working properly.  When I first wrote the automation it worked.  I listened to the entire 7 minute song and it worked.  You could hear the delay turn on and off when it needed to.  I mixed the song down to stereo for mastering and the effect was gone.  The mix down is not the issue.  upon opening the project again the automation is there and you see the effect being turned on, However, you can not hear the delay actually working.  Is this a glitch?  Or am I doing something wrong.  I've seen past threads with this sort of thing, but would think if it was a glitch, it would have been taken care of by now.

Which parameter are you automating?

Try this for a test / work around. Not that it will work, just a hunch.
 
Make sure when you export, that the track in question is selected as the selected track in Sonar.
Not so it will be included so much but the selected track gets it's prochannel in the inspector where external control of the parameters is 100% working. If your track isn't the current strip then your strip is going to use it's own copy of the PC seen or not, and external control and presumably also automation is hit or miss of the grandest. Don't ask my why this is since new SONAR, but I've been on em about it.
 
I'd be really interested as to whether this worked for you by the way.

You have to have the read button illuminated.

Read buttons are all illuminated on every track.  Might be coming to a quick conclusion, but I think the issue might be with the Overloud VFK Delay plugin that is bundled with Sonar.  It didn't matter where I it (pro channel on vocal bus, prochannel on vocal track, and FX bin on vocal track) it worked the first time you hit play then after that it may or may not decide to work with automation.  Automation was only used to turn the delay on/off.
 
For S.A.G, I tried using the Blue Tube Tempo Delay and it works perfectly.  I am able to automate the bypass button.  It works every time during regular playback and in mix down.

bitman
Try this for a test / work around. Not that it will work, just a hunch.
 
Make sure when you export, that the track in question is selected as the selected track in Sonar.
Not so it will be included so much but the selected track gets it's prochannel in the inspector where external control of the parameters is 100% working. If your track isn't the current strip then your strip is going to use it's own copy of the PC seen or not, and external control and presumably also automation is hit or miss of the grandest. Don't ask my why this is since new SONAR, but I've been on em about it.
 
I'd be really interested as to whether this worked for you by the way.

For mixing down, I normally only select the main tracks, never the busses.  However in this case I did select all tracks including busses with no success.