I sent it before the deadline, and it arrived on April 21st. Indeed, the IRS representative said that they are way behind and that my return was likely not processed. I then requested that she check to see if they received my return, and with that search she found nothing.
Some years ago I had called about something I sent and the representative at the time was able to confirm that the forms were received but not yet processed, so it seems clear that they put it into the system even before processing it ... but maybe you are right and my return has not yet even been logged in as received yet.
She did a bit of research and found for the case where a return does not show up anywhere on the system after 6 months, the official procedure is to have the taxpayer re-file.
