That's right - I couldn't believe it either & thought it was some glitch, till I rec'd the interview letter in mail. Like everyone from this FO, wasn't expecting any progress until Dec '18 (estimated case completion time).
Can I ask you where you live? Because it says Dallas service center, but the Newark NJ district office? I am trying to figure out what office is processing my case. Mine says National Benefits Center, but I live in Chicago, and if you go online there's no timing estimation for National Benefits Center for N400.