did you try playing it in another device?
Since this bug is on PC version, i tried android one and it's working just normally. Will stick to android then.
Apparently i found out this also happened on other VN as well and the dev said it's like isolated bug triggered on certain individual user, not everyone. My drivers were up to date if it's one of the factors causing, but i'd like to know if there are any other causing. Thank you kindly for the response!
Edit: No i didn't fixed anything, just pointing out some of my thoughts about this bug since the other dev also figuring out why this could happened sorry for my bad english! X'D
Still couldn't enjoy PC version though, so i have to play with android version for now