My visa was filed on Nov 2011. Received RFE early March. Upgraded to PP along with RFE response and received petition approved on June 11. However my petition is approved from Oct , 2012 as against the expected Oct, 2011 or the petition approved date. Looks like my RFE response was accepted in 2012-13 quota as against the originally filed 2011-12 quota. Have you seen anyone else report such an issue? Can this be an error on part of USCIS?
I think its an error from USCIS part. The valid start date should have been 1st October 2011 or the requested petition date (if its later than 1st October 2011). You should check with your petitioner/attorney to get this clarified. They can get back to USCIS to correct it.
Did your employer amended the work start date to 1st October 2012 along with RFE response? I am not sure if this is even possible, just a thought.