Please state in which country your phrase tends to be used, what the phrase is, and what it should be.
Example:
In America, recently came across “back-petal”, instead of back-pedal. Also, still hearing “for all intensive purposes” instead of “for all intents and purposes”.
I like your comment for the most part, but:
This is assumptive and prescriptive. The link I sent demonstrates that it’s been used extensively and for a long time by people who not only read books, but write books. I’m on board that “set foot” is the better phrase and likely to be the earlier one, but trying to dictate which is correct is - respectfully - a fool’s errand.
Yes yes I know all that. Prescriptivism is bad, tut tut!, a serious linguist only describes language, etc etc.
But whether it was 400 years ago or yesterday, to me personally it’s thunderingly obvious that “step” comes from a mishearing, all while being inferior in every way. It’s even tautological, since the “foot” is already implied in the word “step”. It’s like saying “He was hand-clutching a bag”. One is short, logical, and respects grammatical convention. The other… isn’t and doesn’t.
Occasionally great new coinings come about from mishearings (can’t think of one right now but they exist). This is not one of them.