Gallery columns

For some reason my gallery columns just don’t work correctly. For example, I want 5 thumbnail images in a row, with the space between the images, and the borders, but this entry (https://heart-trick.com/?p=162) to make that happen actually has the gallery column number set to 6, even though there are only 5 images, it sets the spacing the way I want.

This entry (https://heart-trick.com/?p=170), even though it only has 4, also has a gallery column number of 6, and the spacing is how I want it.

But when I put 6 in this entry (https://heart-trick.com/?p=151), the spacing is totally messed up. I don’t know how to fix it. Please help! I tried to read the other posts, but they didn’t seem to apply since they just wanted to remove the borders, or smush them all together.

I’ve already tried changing the number of default columns on media.php and it didn’t change anything. I think it must be a theme problem, I use modularity-lite, but I haven’t used another theme, so I’m not sure if it’s a gallery issue or a theme issue. Please please please help!