Comic covers are smooshed together in my library

A month ago I made some changes to the comic cover width and height but found it too large in the cover preview panel. So I reverted back to the measurements as shown in this screenshot. However, it appears to have no effect. Any idea how I can stop this cover overlapping?

edit: So while writing this I've checked again and it appears to be correcting the cover size in some cases but there are still large chunks of covers overlapping.