So that's probably the problem
The progress with Katia has to be progressive, if you increase the points artificially avoid scenes, and changes in variables of the programming, which causes these problems.
Maybe if you lower the points again and make a few repetitive visits to her apartment you can solve it.
It's at 107. I'm not sure if I'm missing something - I'm not seeing any options aside from Repeat or try new exercises.
Annoyingly I've accidentally completed the main arc and over wrote my previous save just before kicking it off - net result is I can now not go back (arg) - I only had the katia line to complete
I sense that you have also used cheats, because with Katia it's impossible to reach 107, the maximum is 100, lol
Please, if you don't want to have problems in the game, don't alter the affinity and sexuality points artificially. It's also not recommended in the study points, although if you want you can use it to go from 15 to 50 more quickly, because there are many.
On the other hand, there is no problem in increasing money, tenant points, or speed.