On the main 8829 sheet (called the line 8 calculation smart worksheet).

Have you looked at line 8 on each of them?  I suspect that is what is jamming things up.  The law is weird about that so when you enter less than 100% then line 8 gets freakishly small and won't allow the deduction.

While the law is weird and ProSeries correctly doesn't allow it when it is less than 100% and only ONE home office, my first thought that is NOT the correct treatment when there are two home offices.

You can either override line 8 of the 8829s, or enter an imaginary amount on line C2 of that worksheet to get line 8 to be a positive number to allow the office deduction.