Are you playing on Normal difficulty or higher? Easy difficulty prevents you getting from the high-stat endings.
Thanks for the report. Are you using the Original Sprite DLC?
Oh, you answered fast! I was either on hard or normal with the new sprites. I know that easy prevents stat bad ends. Thing is, I could get them before the update on normal/hard.
Just got flirty's bad end by slacking off until promiscuity and sexiness maxed simultaneously. When I max them manually and individually, nothing happens. Normal mode.
Unsure if a typo or meta humor: when you choose to not answer the door for the detached personality, MC says "I'm going to answer it. No one's going to tell me I can't" and then immediately answers.
Found another: 
Alright, thanks. I can recreate the problem, but there... doesn't seem to be any particular reason for it to happen. The code itself is unchanged from the previous version, and there are no logic errors in it. I'm honestly pretty baffled. At this point, I can only assume the bug has to do with a game engine update, maybe? I'll keep looking for ways to work around it.
Yes, that choice is meta humor, not a bug.
Fixed, thank you.