Hi, i have the answer. I asked this over a year ago in the Steam Forum of Sonar. Read it here:
http://steamcommunity.com/app/293140/discussions/0/412446890551877957/ The answer from Support was:
There's a known issue with BitBridged synths being frozen and not having the renders adjusted for the reported asio latency. The larger your latency is, the bigger the de-sync you'll see.
There's currently a few workarounds.
1) Use 32-bit SONAR when manipulating 32-bit only synths and bypass bitbridge.
2) Bounce the track instead, and setup a Process > Nudge command to be your exact buffer size (which you can find under Edit > Preferences > Audio). This is one feature you don't get on a frozen track.
Freezing is already doing a bounce, but you don't get as many editing options as you do when it's a regular clip.
Personally, I never use freeze anymore because of the limitations.
3) You could switch to a different driver mode during the freeze/bounce down.
I know these aren't perfectly ideal, but you should be able to get past your block point and continue working.
FWIW: Dropzone is a very light synth. I just testing with over 10 instances of it on a VM and didn't see the performance change much. You could probably get away without freezing on it in most projects. Z3ta+2 on the other hand is a very intensive synth and if you're having problems I would definitely recommend freezing/bouncing.