Because the email I got from TurboTax said it was rejected. When I re-launched the TurboTax software, it guided me through what happened - that is where it said there was a duplicate 1099-R but gave no reason code. I know what the issue is (failure of either TurboTax to uniquely identify the forms during submission, or failure of the IRS to properly define their file layout to be able to distinguish uniqueness upon receipt).
