Sometimes when I am editing clip automation, the automation will suddenly stop working and the clip plays back as though there was no envelope present. It will only start working properly again after closing and re-launching Sonar.
This doesn't happen often, so I tend to forget about it and move on. But over the years it has occurred many times in total and over several different versions of Sonar and running on different platforms. Maybe other users who do a lot of clip automation editing have experienced the same thing. But obviously the problem is difficult to reproduce.