Menu suddenly sometimes chaotic. No changes made to custom css or theme or menu!

When I try to fix it by editing the appearance – either using the “Yellow Pencil” plugin or the default “Customize”, the menu appears properly! Nothing to fix! But in reality, it’s still broken.

I tried: “Clear theme cache” “Clear site cache” “Delete cache”. No change.

Three days ago the line spacing between menu rows went from approximately the same height as the text to around 10 x spacing. Later that day it went back to normal. Two days ago it returned to around 10x, and it has stayed wacky like that.

Affects every page on the site.

I made no changes, so how / why did that happen? Or more directly: how can I fix it?

The page I need help with: [log in to see the link]