Glitch in the Theme?

I’m not exactly sure what is going on. I don’t think I did anything to make this happen, but I definitely could have. Whenever I click on older posts at the bottom of the screen, it starts expanding all the posts in the column. It removes the featured image, and shows my post. Before it would just have the title, the featured image, and when you clicked on that it would take you to my post, but now it is showing them on the front page. Any help would be greatly appreciated as I am not sure what is going on…