Thanks for the comments, Ivan. In fact, as I mentioned in my edit at the bottom of my last post, I found that I had set the "break angle" for CV operation to 1deg, a silly number, and that was the cause of my problems. Fortunately, I have seen the effect of non-CV mode previously and was able to identify it fairly quickly - then it was just a matter of trying to find out how I had managed to disable it or what parameters neede adjusting. I have not had a chance to retry an adaptive clearing toolpath since then, but it is working fine with other, less demanding but still showing stop/start effects, toolpaths so I'm happy now.