Hello group. This is the OP.
It's been a long time but I have finally reached the end of my journey so I thought I'd go ahead and update it here.
The time between receiving the notice and the actual interview was extremely stressful. We ended up consulting a lawyer who said "It's most likely a clerical error, and I will not be able to help you much since your case does not have any issues (e.g. criminal history, etc.)". We decided to not retain counsel and went for it ourselves.
On the day of the interview. We showed up at the USCIS office, and after some time an officer (different one than last time), came out and called our number and said to us " I don't think that you should be here...". Let me tell you, the relief I felt was unmeasurable. She ended up putting us with the same office that did our initial interview - and he was just as surprised that we were there as she was. He pulled up our case and said that he approved it, but for some reason, it was still open in the system.
After some digging, he told us that there was an I-130 interview scheduled for APRIL 2023 at 10 PM (we got the notice in the summer).
Plus, this interview got scheduled AFTER our 485 interview. All in all - a big system error. However, the officer could not override the system on the spot. So he ended up calling some sort of IT department and started a case to clear it out.
At this point he said "I did what I could, now you have to wait", and we left. I received a confirmation of the ticket request that said if I don't hear back in 60 days I can get back to them.
Well... I did not "hear" back. And just as I was getting ready to write them a message, guess what... my GREEN CARD just SHOWED UP... out of nowhere. No follow-up, nothing. All the approval letters and the card came on the same day.
So it is over. My current journey. Next step - citizenship
But hopefully, this will serve as a piece of information for others- according to the officer who worked on our case, USCIS updated their systems and they are VERY faulty. A lot of system errors, delays, etc.
Thank you all!