I definitely think that this is an interaction between SONAR specifically and EZD2. I'm wondering if SONAR scans a plugin for the number of outputs it has and doesn't expect the count to change. EZD2 is just "ezdrummer.dll" as SONAR sees it, possibly. So, the last time SONAR scanned the plug, it had eight stereo outs and now it shows up with 16 stereo outs.
Has anyone tried, rescanning EZdrummer? When I opened SONAR the other day, I didn't notice if it rescanned the new version.
Most times when I'm using EZdrummer in SONAR, I'm throwing together ideas and building midi performances so I use just a stereo out. When I get down to mixing, I switch to Superior and multi out.
Like I've mentioned elsewhere, I've opened Studio One Projects and Pro Tools projects where I used EZdrummer (prior to the beta phase for EZD2) for Latin Percussion in multi-output mode and everything is working as expected.
I have but one computer so my testing is done on a production machine and with the exception to a common niggle that PT has with all multi-out synths and it's version of track presets (and we work around it) I didn't run into a single thing that caused a problem that stopped me dead in my tracks like you guys are experiencing.
I am confident that Toon will be jumping on this right away because you never catch all the problems until you let the civilian hordes loose on a new software release. They know that, so updates are always scheduled soon after a release.