I don't want to sound rude nor criticize your game (which I like very much), but give you some constructive feedback.
I think that you did the Evaline route wrongly in this update, everything else in the game is fine. It seems that you basically have forgotten that to be able to go shopping with Evaline, Viv must not invite Des to her place. So, until party, she hasn't kissed Des yet, nor she saw her naked, almost she has not flirting with her at all and she has not even shared the bed with her. Still, Viv and Des can have sex together? Not even them alone but in a threesome? Out of nowhere? Being Des supposedly straight? That doesn't make sense at all, in my opinion. Everything happens abruptly, at the contrary to the other paths.
The other thing is that it feels weird inviting Eva to the party and be obligated to spend more time with only Des. When someone invites you to a party where you don't know nobody, you expect to partying with the person who invited you, not that you will be by your own, as it is happening with Eva in the party. What kind of invitation is that? All the situation feels out of place. Besides, Viv told Eva in the shopping scene that she was anxious to see her at the party, but when Viv is there she doesn't even bother in look for Eva. I think it's not what the player was expecting.
I suggest to consider changing that event (in the eva route) in the future, if you are thinking in redone some scenes for the ultimate version of the game. I don't know what other players think, but it seems that event generated confussion in other user here too.