Perhaps I have found the source of the problem. During building the app I have resigned from local login/registration strategy but did not updated mongoose Schema for users collection.
Charts came from recharts.js library, but my implementation is not flawless - when you vote it’s changing colors, because I also use random color generating during every component update, but i consider is as a small flaw and good lesson learned
Just tried again and it worked. One potential improvement could be limiting votes, it seemed like I was able to add as many votes as I liked to an answer.