IRS had a real problem with fraudulent refund returns.  There are 8 billion people who could be filing these, and claiming a refund of phony withholding or other credits (like the "stimulus" payments).  What would make sense is to allow zero AGI when there is also zero payments -- and maybe, that's what they have done.  Should they have announced it?  How many other preparers have a practice like yours?  Don't clutter my inbox with news of black-swan events.