Small addition here: the player character beeing barely mobile is treated as skinny when getting seated in public transport. Happens when going to the theme park, (maybe at other locations too ?).
This was working for me, but I wonder if you tipped over into the immobile category (perhaps through fitness decay), causing the default slender text to be used. I've changed this scene, so if either you or the girl is immobile/enormous, it'll use the barely mobile text.
Yes, both of the female/female couple where close to immobility, was testing out who gives up earlier, so it might have very well been what you have fixed ;)