The UT partnership Sch K and the analogous K-1s look weird enough that I routinely memo "Your net UT source income, after rounding adjustments, is $X" on my K-1s. That said, I don't think I've ever seen the problem you're having - Line 15 of Sch A matches both the sum of column E on Schedule N and the net of the UT column of Sch K (to within a few dollars, because rounding).

Mine apportions to 6 states and allocates to one, but there's probably no overlap other than UT between yours and mine. Mine is oil & gas, but the industry-specific Utah weirdnesses affect the apportionment percentage, not the calculations based on it.

If you look at your Override Diagnostics (a page on the Forms tab), are any of them relevant? They don't necessarily pick up all the items that can change a calculation significantly, but sometimes I find stuff there. I assume there are no relevant items on the Diagnostics tab.