Auto-punch records from cursor start....

But note that Reaper still records from where the cursor starts, and it records all the way to where you hit stop. It only just shows the recording in the "punched in" time selection. And all of this is a good thing...

You also see the recording immediately, if you start recording in punch mode and for some reason stop it before the cursor reaches the punch-in point. -Data

You have no idea how many times I've gone to record something and realized, halfway through, that it's set to punch in and I'm nowhere near the time selection. Yes, this is a very, very good thing. :P

Oh right -- how clever. Reaper is a marvel. Can I ask a dumb question? How do you recover (or even see) the pre-punch recording if you decide you want to keep it?

Just grab the left edge of the item and drag it left. -Data

Or, if you're not at the punch-in marker yet, it'll show up as if it were meant to be recording that way when you hit stop.