"Keep this in mind: If you ask the credit bureau to report a date for this missed payment, it may lower your FICO score in the short term."
Sure, that's true if the late payment occurred more recently than one year ago.
But, considering that SEVEN years of late payments are reported, it is MUCH more likely that the correctly reported late payment will IMPROVE the scores. And most consumers will know whether they had any legitimate late payments (over 30 days past due) within the last year.
Fair Isaac deliberately discourages LEGITIMATE consumer disputes.
So, Fair Isaac's advice SHOULD read:
If you know that you did not have a late payment in the last year, ensure that the credit bureau obtains the date from the creditor or deletes the late payment.
The million dollar questions:
1) HOW does it happen that a late payment is reported on a consumer credit report WITHOUT an associated date?
2) WHY is Fair Isaac rating these UNDATED late payments at all?
3) Why is Fair Isaac rating these UNDATED late payments as if they happened one year ago?
The answer is simple:
To lower consumer credit scores as much as possible.