The first one: the three-turn task of this private server is not perfect at all, which means it can't be done. I've played a few of these private servers. Because they all have another way of three turns.

The second type: incomplete conditions. Inadequate preparation of materials or lack of skills.

As you said, the so-called "service talents" and "light adults" should be occupations created by the assumption of private servers themselves, which are not given to the production department by default at all, and naturally cannot solve the three-turn task of the production department.