Nope, something is definitely wrong with your game, I've tried different choices/routes and here is the problem:
When doing the Bituka questline up to her photoshoot, you have to pickup a bag at her house and there you meet Julie. If you reject her her questline is closed, which is ok. But if you fuck her her questline is closed too, which is not ok, and Bikuta’s questline is closed too, which is understandable as you missed her photoshoot.
So I thought I did something wrong and did another playthrough by completing ALL of Julie’s quests first. Ok, good, now I can concentrate on Bikuta’s questline seeing that it’s still not closed. So here we are at the photoshoot quest again, you meet Julie and if you fuck her, exactly the same happens, both questlines are closed.
So what I’m saying here is that both Bituka’s and Julie’s questlines are opened till Bituka’s photoshoot, then 2 scenarios happen:
1 – you reject Julie, her quesline is closed but you can continue Bikuta’s questline.
2 – you fuck Julie, both her and Bikuta’s questlines are closed.