Quick Draw flaw

I can reliably land a Quick Draw one-hit knock-out on every character except Jigglypuff and Game and Watch.

I have never landed a QD-OHKO on Jigglypuff or Game and Watch...

I realize no one could care less if we can't use one of several one-hit kill options on the lightest characters, but is this a known issue?

Has anyone had success or know anything regarding this?