The income is updated only at the beginning of every turn. The screenshot is maybe taken in frames between two turns (i.e. after you moved a unit and expanded your territory).
Edit: false info, just ignore my comment, sorry 
The income is updated only at the beginning of every turn. The screenshot is maybe taken in frames between two turns (i.e. after you moved a unit and expanded your territory).
Edit: false info, just ignore my comment, sorry