Section 1231 Gains - Entering a GAIN caused my Taxable Income to go DOWN?

I can't really wrap my head around this, and think something may be off.

 

I have a K-1 with a box 10 (Net Section 1231 gain (loss)) of +6,383.  Box being -1,879 -- so still a ~4,500 overall gain

 

After entering POSITIVE 6,383, my Taxable Income is going DOWN.  

 

I thought after entering that gain my "Federal Tax Due" would be worse, but it actually flipped to a refund.

 

Was a pretty vanilla K-1 with nothing crazy.   I can almost see, best case scenario having no tax change (due to offsets/carryovers), but this doesn't make sense.

 

This can't be right, can it?  Would love some help