If a film looses RATINGS (like 1,000 of them) what happened?

Hello IMDB community, it appears it is possible to lose ratings - I noted that our page lost 1,000 user ratings suddenly one day - wondering what happened to them?  Here is the page: https://www.imdb.com/title/tt9191700/

Is this a flaw in the system?  Are people hacking IMDB now?