All of the above!
60, or even a 100 tooth blade, a little higher, with a backing board.
I also noticed that you cut 2 pieces.
More of a burn on the 1st piece, and it seems to be burning when you back the piece up.
I'm not a fan of the eraser hold down.
It's possible the blade is no good, and it might be pulling the piece back into the blade just enough to burn it.
I would try a few runs going all the way through, past the back of the blade, just to see what happens.