Slot is wider than the blades it comes with
Their was junk at the bottom of the blade fixture, and it only took a fraction of material for the blade to behave erratic. I took apart the blade runner completely and cleaned it. I don't know what I did other than that, but after that it ran completely fine.
Inside the slot down past the top of it, I believe it's a taper from 0.1mm down to the size of the blades. This allows the blades to flex so they don't completely snap when horizontal force is applied to the blade.