FTE w/ Zenith ZF-5k

Hi everyone, I recently purchased a ZF-5k for the holidays and had an FTE malfunction 10 rounds at my local range today.

Before firing, I took the weapon apart to clean it. I used the recommended ammo, 124 GR NATO, manufactured by Monarch.

Based on the pictures, could someone tell me the dictator of the issue? I read that replacing the extractor spring with HK solved the issue for some, but would it be applicable in this situation?

Thanks everyone