Things disappear/reappear randomly

The items in my tabs inside the “Discover” menu, under “Customization”, keep disappearing.
When the page first loads, there’s no pet in the center, but if you click pet names, they pop up.
Also the items that are supposed to endlessly scroll at the bottom of that section also keep going away and then they come back when I change something…
Right now they don’t show up at all, what gives?

Here is my site Read-only: [LINK]

Anyone, please?
This forum… It rarely gets any replies, is there a better place to get help? Jesus…