Hey, at least they're exactly offsetting amounts! 🙂

This is really, really hard to track down. Looks like the last time I had it was in 2015, and my notes from then say "This, and similar adjustments on other state returns, are related to the -1 in Vacation Home Depreciation. Without the -1, there's an erroneous carryforward for the state. With it, the tax return is wrong. Delete erroneous carryforward after 2016 proforma." (Note that this entry has exactly zero to do with a K-1, although the return itself included information from multiple K-1s.)

My suggestion is to use Screen 51.041 to enter offsetting amounts in Other Subtractions (Ctrl+E) and Other Additions (Ctrl+E). Use "Other Allowable Deductions as the Other Subtraction type; that will generate a 99 code. In my experience, you may need to use trial and error to determine how much to enter; for reasons that are not clear to me, whatever is generating the oddball output sometimes "adjusts" for manual attempts to offset it.

If you have time, you can try emailing the data file to Lacerte and asking them to see if they can identify where it's coming from. Sometimes you get lucky and the person who looks at it notices something that looks familiar. But it took me (literally) hours to figure out where mine was coming from last time, and I had an Excel file that already told me what I expected every number to be.

Other stuff that might be a possibility: depletion weirdness (limited for federal but not state, for instance), multi-state weirdness (the way you enter multi-state income isn't the way Lacerte expects to see it), diagnostics that say "you didn't code this deduction to a state."