Why is the NBC mailing address being printed on the receipt notices?
The NBC will serve as the hub and conduit for USCIS Field Offices and will house files onsite until cases are ready to be forwarded to the appropriate USCIS Field Offices for interview. As such, customers should utilize the NBC address provided on the receipt notice for forwarding any additional information or related correspondence.
If you are filing only I-130, you need to send it to the service center that has jurisdiction over your area or residence. If you file I-130 and I-485 concurrently with other applications, you need to send it to the NBC where; I-130 is processed and sent to the service center where it waits for a visa number fron NVC; I-485 preliminary processing is done and it is sent to the DO for further processing and interview preps; I-765 and I-131 are processed at the NBC.
If you look at the case processing tables here...
https://egov.immigration.gov/cris/jsps/ptimes.jsp? you will find that I-130 for immediate relatives and others is processed by the respective service centers and not the NBC. There was a recent memo from USCIS regarding transfer of cases to the CSC to reduce backlog in other USCIS offices, so my "best guess" would be that NSC transferred I-130 for spouse to CSC for faster processing.
My $0.02