Gallery only displays 3 columns

I’m having trouble with the columns when adding a gallery. I want to have 4 columns, but when I select 4 columns it will only display 3 columns on the home page, with the 4th column below all by itself. However, when I click on the post itself it will display the 4 columns how I selected. How can I fix this so I can get 4 columns on the front page AND in the actual post page?