Yesterday, my wife received a reminder letter from USCIS to file her i 751. I am confused as if she needs to. At the time of the interview we were married less than two years, but we waited until after two years for her arrival to the us. Also, zero previous tourist visits to the us. When she arrived to the us, the official marked ir1 visa, but only after I reminded the officer about the two year marriage rule. When the green card arrived in the mail, it was a 2 year cr1. We filed a i90 and later arrived a 10 year ir1 green card in the mail. Then, yesterday the reminder letter from uscis for 1751 arrived. I am very confused why the letter arrived when we already filed an i90 and have a 10 year ir1 green card in hand. Should we call uscis? Or ignore the letter?