Have you checked “Faithless Elector” laws?
Show me one elector that has been sent to jail for changing their vote.
Second thing, they can only be punished AFTER they cast their vote. It either is recorded as they voted or voided depending on the state.
Third thing, some of those states use secret ballot for the electors. There's no way in hell you can get a conviction for a faithless elector law in a secret ballot.