回複：F4, 回複863211， 孩子申請是在她父親入美國前。

That is why USCIS denied the kid's I-485 because the kid was not qualifed for filing I-485 before the father (primary applicant) entered US with the immigration visa. Now the kid just needs to file a new I-485 again if he/she has a legal non-immigration status (e.g. F1) and he/she will be fine. So, don't worry.