Murphy's law: To further add, I got a Request for Evidence (RFE) from USCIS for missing my 'Flu Shot'. The civil surgeon must have skipped recording my flu vaccine as I filed my I-485 during summer. Late winter when my I-485 application was supposed to be approved, it was put on 'hold' due to a missing flu-shot.
Long story short, I took a flu shot and sent my updated vaccine record to USCIS. Got my Green Card approved within a week.