Why did NTA release final key after the release of candidate's percentile card?
Nothing can be said about it as you know JEE Main 2019 is being conducted twice by NTA for the first time. The final answer key has confirmed that there are in total 22 wrong questions in JEE Main 2019. These questions have been dropped and full marks have been given to the candidates. You can check the further information with the given below link.
https://engineering.careers360.com/articles/jee-main-answer-key
Good Luck!