Safari
Yeah it is nonsense. A propjet is a jet engine. Recruiters just tend to make these ill-thought out rules as a selection device. Years ago, with turbo & pure jet time, I was rejected by CX because I had "no underslung jet engine experience" ! No kidding, I still have the letter.
Very sorry to note your position. Keep banging on the doors & someone with some sense might grant you an interview. Bon chance.