troika

my theory is, the local office probably requested the i751 file to prepare or schedule the interview for the N400, but since most of us didn't do an interview for the i751 in the first place, due to covid or whatever, their computer system probably require them to enter something to make that happen, which triggered an automatic i751 notification too.

reused

I had the same notification about a month ago and today I got my N400 interview letter

Let us know what they say, I got the exact same notice today in the mail, very strange ! Do you have a citizenship application pending ? My I-751 was approved back in March 2021

your N400 interview I assume ?

Same here, ROC approved in March 2021, got an N400 pending and got the same message this morning. It has to be something to do with the N400, let's see what the letter says.