I have this problem with T-Racks 3 singles plugins. Basically the knobs spring back when I try to adjust them. And Audition will crash / hang if I try to remove the plugin or try to exit Audition.
I contacted the IK multimedia tech support a few days ago but no one from IK has given me any response yet.
I did find this post on the Adobe Audition forums with some info and a work around by using effects wrappers or chainers:
http://forums.adobe.com/thread/463638?tstart=0
But wrappers and chainers use up cpu cycles and can potentially cause latency problems.