I'm not sure if it's just happening to me, but the only way I can gain trust points for Kioko is during the morning class, which only gives 5 points.
Her library interaction seems to be bugged, it says it has given me 20 points after the interaction, but the points stays the same.
It would be fine but the grind is going to be a pain.
Edit - This started popping up when I did the reading books with Kioko interaction as well.