Bounce to wav -timing is off

Not sure.
 
Latency shouldn't matter one bit when it comes to bouncing.
 
What is it you're bouncing - tracks or synths?

Sorry, misread your OP, so ignore some of my post.
 
Still worth trying BounceBufSizeMsec=0.  That solved lot of timing issues for me.

BounceBufSizeMsec=0 is the default. It tells SONAR to use your realtime playback buffer size for processing. It shouldn't matter, except in the case that you're using Bitbridged 32-bit plugins; Bitbridge has a bug that will add an empty buffer of audio to the synth rendering (whether by freeze, bounce or export), making it play late. The larger your buffer (or the larger you set BounceBufSizeMsec) the later it will be. A smaller buffer will help minimize it, but the only way to eliminate it is to use Jbridge or a 64-bit synth that doesn't need to be bridged.
 
Of course, this is all moot if the bass part isn't synthesized. I'm not aware of any general issues rendering FX plugins that use PDC, but it's possible something is going on there.

I often bounce the whole project to a "Master Bounce" track assigned directly to Main Outs rather than exporting/importing. Shouldn't be a problem; it's all the same rendering code (per Noel), just different destinations.

Are you using Fast or Real Time bounce?
 
If fast, try slow. (and audible - so you can hear what's happening)
 
 

Is it your bass track that is delaying or all bass frequencies? I'm assuming the first. Is it a synth bass or a recorded one? Are there any other plugs on the track? Does it go through a buss or straight to the mains?

M_Glenn_M
 
It was the bass which was a DVI fender bass.
Yes it goes to a bass buss
This synth could be the problem as it couldn't find it on boot up.
That plug no longer loads but that's another unsolved story.
It plays if frozen but not if unfrozen.
This must be the problem.
I tried switching to a new synth SI bass but it doesn't play all the notes.

 
Dropped notes are most likely due to your MIDI Prepare Using buffer being set to the new default of 250ms. Try increasing to the old default of 500 in Preferences.
 
And it looks to me like the Sonivox DVI Fender Bass is only available as a 32-bit plugin, so Bitbridge's bug may well be responsible for the delay. You can correct for that by dragging the frozen track back by the equivalent of one buffer or just making sure you render with your ASIO buffer set very low ( a couple milliseconds shouldn't really be noticeable).
 

M_Glenn_M
(My setup is 32 bit)

 
Oops. Totally missed that; kind of assume everybody's x64 now. In that case, the whole Bitbridge thing is irrelevant, and buffer size should not affect render timing.

It certainly sounds as though it's the plugin that's causing it, so I'd seriously consider replacing it with a different synth.
 
There are some GREAT patches in Dimension Pro, Rapture, and the one in Studio Instruments isn't too shabby.
 
Just a thought.