Having trouble with scoping

Hi, so I'm learning Statamic and making my first site.

I have a navigation with a submenu of entries that show the name and short_description(optional) of the entry.

I'm using the nav tag in the template file that looks like this:

{{ nav handle="main_menu" include_home="false" }}
    <li>
        {{ if children }}
            <span>{{ title }}</span>
            <ul class="sub-menu">
                {{ children }}
                    <li>
                        <a href="{{ url }}">
                            <h1>{{ name }}</h1>
                            <p>{{ short_description }}</p>
                        </a>
                    </li>
                {{ /children }}
            </ul>
        {{ else }}
            <a href="{{ url }}">{{ title }}</a>
        {{ /if}}
    </li>
{{ /nav }}

This works fine until I'm on a page of an entry that has a short_description. This will fill in all the empty menu items with its short_description.

I have looked in the documentation and tried various things, but can't seem to find the right solution.