So I called NSK and the guy said it sounds like the interior of the collet is scored, which is what it looks like in the pics. Apparently these little collets are a one and done type deal, they don't really handle failure well. I suppose I'm extremely lucky to have used it successfully this long with all my learning failures. I guess I'll purchase a new one and see if I run into the same issue and report back . . . in the meantime, maybe I can try clearing with my 1/16" end mill. Less force on the collet?