Regardless of which side the problem it’s on, the cause is the same - duplicate entries based on what they deemed necessary to call it “unique”.
My guess is that what they consider “unique” is FEIN (payer ID number) plus distribution amount, and possibly tax withheld. That isn’t enough pieces of information to make it unique.
I don’t think the taxable amount matters here - at least in my case I only added the penny to the distribution amount and it worked.
