The online notification webpage can be very unreliable. I would call the toll free number or schedule an infopass to double check what the current status is. If the green card was approved, there is no need for advance parole document.
This answer is for informational purposes only and should not be construed as legal advice.
I agree with my colleague that you should call the USCIS number on the website with your receipt numbers handy to find out more about the status. Good luck!
The answer above is general in nature and provided for informational purposes only. Specific and reliable answers will require a better understanding of all the facts and information about your case. You should consult with an attorney who can analyze the facts and law specific to your particular situation. Please be advised that the answer does not constitute legal advice and may not be viewed as establishing an attorney-client relationship of any kind.
You will likely get a more accurate answer by speaking to someone either on the phone or in person. You can either call the toll free number or book appointment in infopass. Here is the link to infopass: https://infopass.uscis.gov/. Best of luck!