Adjustment of Status - I-485

Case Type : i130, 131, 485 , 765
F1 to COS ( Married to USC)

10/8/2019 - case was filled
10/17/2019 - Biometric Notice
11/8/2019 - Biometric Done
12/3/2019 - received RFE for I-485 - spouse income was less
1/6/2020 - RFE response received at uscis
1/10/2020 - Courtesy letter for not submitting the i-693 medical
1/16/2020 - Ready to schedule your Form I-485, Application to Register Permanent Residence or Adjust Status, for an interview.
1/30/2020 - We scheduled an interview for your Form I-485,
2/27/2020 - Received EAD
03/18/2020 - USCIS Cancelled Interview for corona virus ( It was on 3/19/2020)
3/19/2020 - Case is ready to schedule form i-485 Interview
4/27/2020 - we sent a request for initial evidence for your Form I-130, Petition for Alien Relative, ( dont know what they are asking )

I dont understand why after scheduling i-485 interview , they gave RFE for i130. I asked my lawyer and he said i485 and i130 are technically separate applications and most of the time they are reviewed at the same time during the interview.