You'd be forgiven for thinking so! It comes from Japanese, yoke (除け) meaning protection and poka (ポカ) meaning blunder, careless mistake, or error. Although it looks as if it would rhyme with joke, it's more likely to be said yoh-kay. If you're curious, paste ポカヨケ into Google translate, select Japanese, and hit listen :)
(I suspect OP knows this -- the question I think was meant to be a sly way to say "are you supposed to say yoke like yolk so that it rhymes with joke, or joke like jokay so it rhymes with yoke")