I had the same problem and reinstalled the bearings, poppet, and springs out of order in the piston. Ball should rest on top of poppet, then poppet in spring and the stiffed inside each of the four holes.
Your situation is exactly what I have on my hands. I also looked up the pictures and have decided not to try to fix this since the manifold will like stay sealed without it. Messing around to take the others out and then still need to remove this and maybe others has high risk of more...
