My part takes a while to slice (on my hardware, at least), and sometimes I realize I’d rather cancel than let it finish. The cancel (which I usually bring about by first typing ‘a’, then ESC, because I can’t remember which should work) appears to be successful. But afterward, I can’t start another slice without reimporting the part. (I’m running under Onshape, btw.)
Verified. And I have a fix that will go out tonight.