The Magus class should begin with trained unarmored proficiency. This is working correctly. Unarmored proficiency should become expert at level 11 at the same time medium and light become expert. This does not work correctly and this proficiency seems to remain at trained instead of becoming expert as it is supposed to.
Additionally, at level 17 this is likely supposed to become master along with light and medium, although here it uses the term “unarmed defense” so you’re interpretation on level 17 may vary, but I think it means “unarmored defense” here as well. The builder leaves this at trained as well.