got same bug too, everything max but boobs stayed at lv4 even though done so many hypnosis training. I think you can bypass it by doing exhibitionist sex or bdsm sex. after that you gonna see the level skyrockets fasti've made her nipple orgasming thirty times , but still cant get process in nipple training.
besides, clit level shows max level in character menu and shows 0 level in Hypnosis state .
someone can help me?