So I decided to just cure her vampirism to get rid of all of this. I don't know it this was because the game thought she was 'a new' vampire and I just didn't notice them doing that or what, she was fully leveled. Also for some reason she would do the animation of being unable to control herself, like when a vampire is thirsty except she wasn't. She would still get randomly the moodlet for eternal sadness, but she also had the new weaknesses, including rarely feeling anything. Every time she would do the normal hissing animations as a part of being a vampire, it would now lower relationships like the hissing weakness. I gave her suppressed emotions as a power and weakness for eating food, I didn't give her the sadness or hissing.
I got tired of her constant hissing ruining her social life, so made her the drink to reassembly vampire points to powers. Gave her eternal sadness and hissing as weaknesses. I play in a different language so I don't know the names for these but hopefully I describe them well enough. Everything I did was in-game, no cheats, and I'm only mentioning the weaknesses/powers that have stayed.
I have the base game, vampire pack and Get together.
