I’m using the [button] shortcode (and actually, that’s a really good point. The documentation around shortcodes is terrible and there’s no way to generate a shortcode within the page editor, which is a bit annoying).
Anyway, any url= attribute with every button doesn’t work.
At the moment on the homepage there is a button to direct the user to my client’s Instagram page. Instead, it just hashes the page and products a “#” URL.