It seems to be a program error.  Now that I think about, I vaguely remember this error from a previous year.

If the taxpayer's income is low enough to qualify for EIC without any children, ProSeries is wrongly automatically required those boxes and it wrongly denies the credit.

Because they have children, I would just go ahead and check the box that they were in the US for over half of 2024.  That answer won't show up on the tax return, but it will trigger ProSeries to calculate it correctly.