I think it's a kind of bug because I got this bug after neighbor teen got back to her house after visiting my house. They were doing homework together but she left her homework on my lot. After that, my teen sim put it back into his inventory himself. I tried to get it away but only his homework book was available to be dragged. I dragged his homework out to the floor and put it back to his inventory, then only one homework was visible. Since that time, once he complete his homework, he just leaves his homework on dining table and there's no interaction at all. I can't see even 'put in the inventory' interaction. No interaction, no explanation when I hover over the mouse on the homework. I tried to reset the homework book but it was of no use. Is the homework purchasable? I don't know what to do. It happens to the red haired boy.
Blond haired boy has no problem with his homework book.