wrong average result after voting

Hi.. I think there is one issues.. I add 6 star voting instead 5.. and when I click to vote and give 6 star I get correct info “6.00/6 (100.00%) 1 votes” but when I refresh page.. or click to open another page and back to post I voted I get this info “5.00/6 (100.00%) 1 votes” .. instead 6 its showing me 5 for average result

https://ww.wp.xz.cn/plugins/kk-star-ratings/