It's been a 'known issue' for donkeys years as have the splitting stocks. I've had a CZ and Zastava which where both tempermental feeders. In Africa you can solve the issue by shooting solids only, ... the factory 510gr Winchester soft was a disaster in both my rifles but particularly the CZ. The CZ was fixed permanently by conversion to 458Lott, the Zastava by shifting to the 480gr Woodleigh soft. In both CZ and Zastava, replacing the Winchester soft with a Woodleigh 500gr was another fix.

Ultimately, get a good gunsmith to iron out the bugs.
Cheers...
Con