This looks like the inserts are worn and were damaged, maybe by someone who thought running pallet wood or the alike through a jointer ...also looks like they over tightened the screws on the cutters. The screws that hold the inserts should be 48-60 inch lbs or 4-5 ft lbs. That Ain't much. If they get over torqued, it causes the inserts to skew and unseat from their pocket/seating location. Also, the outer ones when over torqued when stressed will crack and/or break because of said over torquing. ... Talking from experience.
The seat in many carbide heads do not have (imho) a decent seating pocket, likely because of the added manufacturing cost, you just learn to get the correct fell , then when seating them, 1st just firm the screw lightly, feel the carbide lock in on the detention seat, then tighten to spec.