I've had that before, sometimes on the 511-A and sometimes on the 511-B. Of course, I can't find anyone now who both has it and I've finished far enough to have resolved it. But going by memory, it has had to do with Oklahoma depletion and/or Indian Employment Credit and/or treasury interest / muni interest for my clients.

I zero it out by making an offsetting adjustment to Other Subtractions (basically, trying to net it out to zero, which makes Lacerte forget about it entirely) and then do the return the way I want it done. That presentation isn't one that Oklahoma particularly likes, and responding to a notice with "heck if I know" or even "this is a bunch of things that the 511-A and 511-B has actual lines for" is not my favorite.

Don't forget to manually adjust for your out of state income or loss and any other differences between federal and OK K-1s.