Concentric AI interview questions

Got call from 3rd party recruiter. 1st round was medium leetcode DSA, 2nd round LLD of Encryption Service with Vault for each user, 3rd round was HLD. 3rd round was taken by some new comer who asked the questions which he worked in his previous company. Overall the discussion went very good and I was expecting for next round. But they gave negative review for that round. I was socked coz it went very well. I asked recruiter if she can give exact feedback about that round but as usual she never replied. Overall experience was good but this will be mystery why he gave -ve review even after such healthy discussions.