Otto did a good job of describing how the pedal engagement works. It’s a goofy design, IMO, and if the hole gets wollered out and/or the edges of the hole get rounded off….it will have a hard time grabbing.
Mine only grabs if I push it like all the way to the floor. I’ve managed to live with it up to now, but it needs attention someday.
I have seen where folks file the edges of the hole to a sharper edge to restore the “screen door stop” action that Otto described. One guy on YouTube even added some weld and then filed to restore something closer to original geometry.
Something I’ve considered as a quick and dirty fix: filing a series of little notches in the pedal shaft. I’m not 100% sure if that would even work, and I’d need to study it a little closer to think about unintended consequences.