What happens if i-485 of the derivative applicant is approved before the primary applicant?

So my wife and I filed out I-485 together (EB2). I was the primary applicant and she was the derivative applicant. Her I-485 was approved one week before mine. Although both the applications are approved, her's (derivative) was approved one week before mine (primary). I tried googling this issue and found different answers. For example, the link before says "Generally, derivative applicants may only adjust status once USCIS approves the principal applicant’s immigrant petition. There are exceptions." I am trying to find what those exceptions are but I am not able to find it. We filed our I-485s together.

https://citizenpath.com/faq/principal-applicant-derivative-applicant/