Did you omit to tell us the line number that should be in the diagnostic?

My hunch is that you have created two separate entries on Line 2 for the same dependent with the same SSN, trying to match each line with a different provider on Line 1, when you only need to have one single line for the dependent by aggregating the qualified expenses.

FWIW, the Rule-Number you cited is not among those published by the IRS: https://www.irs.gov/pub/irs-utl/f2441_br.pdf

Hoping to get some extra credits from this answer for my Friday mind reading class so that I don't flunk the semester...