Questions:
1. look at spent brass: Is it smooth and unmarked/scratched down the side of the case?
2. Do you experience the same problem with steel case ammo?
If the answer to these questions are no, see the post on the receiver difference between CSA and other vz.58 variants.
If that is your problem, you can take down some metal of the bottom of front corners of locking piece slot in the receiver with a file or dremmel or just avoid brass and just use steel-cased ammo.
Some Century rifles have serious receiver tolerance issues as well causing the carrier to cycle too low in the receiver. From looking at your photos I don't believe you have that problem.