It feels like I've spent the whole week trying to fix a mistake I made when sharpening this plane iron. I got the angle wrong, and trying to grind it out is taking an age :(
@SamLR have done that. It removes material. But when I move to the diamond plate it's still not working. Even going so far as getting a burr on the paper.
@quixoticgeek weird!
beyond that I'd be tempted to doubt the flatness of either the plate or the surface below the sand paper.
At least it looks like you're nearly there.