Yes, I’ve noticed this myself on 10.6, but can’t figure out what it is that they’ve changed. The device seems to be behaving very strangely when you tell it to change rate - I’ll need to do some more experimentation to try to find a workaround.
Ooops, terribly sorry… It appeared to be a problem with Mac OS X. I noticed that I didn’t get any clicks when changing volume, and preview of audio files was also silent. I did some changes of which audio interface I am using, and that seemed to cure everything. It seems Apple is slacking off a bit on their previously rock-steady handling of everything… Alas.