When killing your target Novikov in Paris with he lighting rig the assassination challenge doesn’t unlock, i am stuck on 28/29 assassinations and tried the challenge 5 times now
(Please note if you are attempting to bring a bug or a technical issue to IO Interactive’s support team’s attention - the best place to post this information is the #player-support category
You may particularly want to check the Known Issues thread:
The issue you’re facing has been reported by some players as well. You will have to wait for a fix on this one.