My renewal was processed in Nebraska, even though I live in NY and sent it to Chicago. It is odd that a lot of renewal apps in Nebraska is experiencing delays. It only took me 3 weeks luckily. I don't know what made my renewal app any different to be honest. The only thing I can possibly think of is that I came as a B2 visitor, had tons of proof in my original application back in 2o12 (elementary school-junior high school-high school report cards and diplomas, unsuccessful green card application, had work authorization when I was like 11-15 years old, etc.). Not sure if that would make any difference though for a renewal.

You should have received letters, including one that says they will be reusing your previous biometrics, in the mail. If you didn't, you need to be proactive here and see what's going on by calling USCIS.