Rating dips to 8.3 from 9.9 with alternate calculation

I recently watched and rated The Kashmir files, but I noticed even though the user ratings are above 9 IMDb is showing it to be 8.3 with a note which says IMDb noted some unusual voting activity due to which they had to choose an alternate weightage criteria.

I wanted to understand why/what and how does it works, or is it just IMDb trying to monopolies the movie ratings by not considering user ratings?