Total cards not accurate in a folder

I have found a few folders where when I filter by the folder will show 5 cards, but the total in the folder totals in the upper left will say like 7. The correct number should be 5. I found if I move all 5 out and filter it will show no cards, but the total above will still say 2. If I then delete the folder and recreate it, it will be right. 

Am I doing something wrong?