E/ L Spouse Work Permit

I applied for my wife's EAD on Dec 6, 2017, after my H1B extension upon getting approved I-140. I completed I-765 on my own without lawyer's assistance. (My company lawyer quoted \$1200 for this. I only paid USCIS fees of around \$400). I sent completed documents to Nebraska center (since Michigan falls under Nebraska jurisdiction as per I-765 instructions) on Dec 6 and receipt was sent on Dec 12, 2017. However, receipt number was starting with EAC meaning it was sent to Vermont.

We received approval notice on March 17, 2018, and EAD card on March 19, 2018. Processing time as per on USCIS site was more than 115 days for Vermont. (As of Jan 31, 2018, they were processing Oct 9, 2017, applications). So I was expecting a response by the first week of April. I was expecting an RFE or denial since I sent wrong I-797 for H1B principal's spouse. (or at least I felt it was a wrong one). I realized it just after mailing it but did not find any way to notify USCIS or send an updated document. I could only notify address change.

I thought of sending an inquiry yesterday. But to my surprise saw an approval notice from USCIS in my mailbox on March 17. I guess USCIS did not send RFE to notice because either I only thought I sent wrong I-797 but sent correct one (I have two I-797, one for approved I-140 and another for H1B extension based on approved I-140. I sent the second one.) or USCIS had the records with them and did not need me resend another I-797.