I suspect that is part of the clutch disc. The disc is a thin metal plate with the material riveted to both sides. If the lining failed and got jammed up in there, it could rip out part of the plate. Could also be part of the sprung hub, but looks too thin for that.
The decel fuel shutoff is on a timer. So the first, short spike is from the transition to off throttle but fuel is still on so it returns to normal quickly. The long spike is the decel fuel shutoff which happens after a certain time at closed throttle as long as the rest of the criteria are met...
None of that is unusual. The long spikes up happen when you go into decel fuel shutoff. The engine stops using fuel, but it's returnless so the pressure builds up since the pump is still going. Note how the FPDC keeps going down to try and compensate. The downward spikes are also normal...