I think the path is forked incorrectly here for those who have chosen to stay more for Luna's massage. If you leave, the value 'luna_d' is assigned and when the scene in the screenshot comes, it checks either for the value 'joe' or 'luna' indicating that the third path is the one that should have the value 'luna_d' and even the dialog alludes to it. The problem now, is that the game treats it as if I left the massage and automatically chooses the third path like the screenshot because the p2d2massage variable should've been assigned the value 'luna' but it didn't or rather the script doesn't even have an instruction for it I assume.
EDIT: I took a look at the script file, It seems that if you're not playing the bisexual route and haven't done anything with Joe, then the non-bisexual route gets called for obviously in the script but there was no instruction like this $ p2d2massage = "luna" in that path. Granted if you still choose Luna in the bisexual route the script fires up correctly. The solution is that I just added that line just before the the dialog begins and right after the 'else' statement and now it works and the scene in the screenshot proceeds with the first forked path like 'intended'.