I received GC with my wife and one minor son (EB1 category). Other minor son's status did not change. Today I am seeing following hard LUD on my son's I-485.

Application Type: I485, APPLICATION TO REGISTER PERMANENT RESIDENCE OR TO ADJUST STATUS

Current Status: This case has been sent for a standard interview.

My lawyer friend also thinks that it may be a random pick for audit purpose i.e. to meet a person and see document (birth certificate etc.).

It is possible that I enquired through senator's office about my son's case. They received the response that by mistake they forgot to process my son's file. They promised to process it soon. And now this interview thing. Most others advise me that nothing to worry. It should be straightforward. What is your advice to me?