We submitted my wife's I-751 in early 2023 and then my wife submitted her N400 in July 2024. Shortly after, her I-751 was approved in November 2024 and she received her 10-yr green card one week alter. Then in December 2024, her N400 was scheduled. But a few days ago, we received a letter from USCIS that we will need to attend a combo interview for N400. In the meanwhile, the online status for I-751 changed from "approved" to "your case was transferred and a new field office has jurisdiction".
So is this normal? anything we need to prepare?