That happened to me a couple weeks ago... but it was awful. I printed the tax return (it was fine) and mailed it to the client.  When I received the signed 8879 forms back and went to electronic file, a quarter of the data I had entered for that tax return was gone!   It was horrible.  Had to have the client PDF all the data I had mailed back to him.  Thank heavens I always look at the 8879 in the computer as a "check it" procedure.   It was about mid March if I recall correctly.   (there might be a bug somewhere).  Due to that issue, I have been over diligent in my check it procedures with every incoming signed 8879.