Hello warrdil, only I-539 was in RFE. I-765 hadn't changed from "your application is process" (the first status that stays for months till your applications moved to the top of the que). I'm assuming that you will get 2 letters if both are in RFE since they are usually "considered" as two separate applications. If your I-765 RFE documents don't reach you in the next week inspite of your online status saying you should expect their email, I think it would be wise to call USCIS on their customer line to notify that you haven't gotten the document they send. Hopefully they might share what document you it was too - then again I'm not sure how much information the call center has. But definitely notify them that you haven't received it. Send your other RFE ASAP. We send it send it through one day Mail on USPS which we could track each step. I mailed it at 5pm today and it reached by 3 pm the next day. Within a week, they usually approve it if all the documents are fine. Good luck with you application! Let me know if you have any further questions I can help you with from my experience.