Menu rendered as taxonomy

Hi,

I use this

[taxonomies]
    iveco           = "iveco"
    linux           = "linux"
    medien          = "medien"
    navigation      = "navigation"    
    programm        = "programme"
    reise           = "reisen"
    software        = "software"
    tutorial        = "tutorials"    
    wohnmobil       = "wohnmobile"


# Definition für das Hauptmenü  Identifier und url müssen GLEICH sein
SectionPagesMenu = "main"   
[[menu.main]]
    name        = "Wohnmobil"
    weight      = 20
    identifier  = "iveco-womo"
    url         = "/iveco-womo/index.html"
[[menu.main]]
    name        = "Hunde"
    weight      = 30
    identifier  = "hund"
    url         = "/hund/index.html"
[[menu.main]]
    name        = "Blog"
    weight      = 40
    identifier  = "blog"
    url         = "/blog.html"
[[menu.main]]
    name        = "Kontakt"
    weight      = 50
    identifier  = "kontakt"
    url         = "/kontakt/index.html"

in config.toml.

In the header partial I create a top level menu like this:

    <nav class="menu-nav">
        <ul>
        {{ $currentPage := . }}
            {{ range .Site.Menus.main }}
            <li>
                <a class="menu-nav-item{{if or ($currentPage.IsMenuCurrent "main" .) ($currentPage.HasMenuCurrent "main" .) }}-active{{end}}" href="{{.URL}}">{{ .Name }}</a>
            </li>
            {{ end }}
        </ul>
    </nav>

and in frontmatter of articles I have something like this:

+++
title       = "Ein Theme für Hugo erstellen - Tutorial Teil 1 - Das Rohgerüst und die Startseite"
date        = "2017-02-25"
software 	= ["Webseiten"]
programme	= ["Hugo"]
tutorials	= ["Hugo"]

+++

Now when I render taxonomy links on the list page for an aside sub menu like this

    <section>
    <h2>Rubriken</h2>
        <ul>
            {{ range $taxonomyname, $taxonomy := .Site.Taxonomies }}
              <li>
                <a href="{{ "/" | relLangURL}}{{ $taxonomyname | urlize }}.html">{{ $taxonomyname | humanize }}</a>
              </li>
            {{ end }}
        </ul>
    </section>

I end up with an entry main in the link list.
There obviously is no taxonomy called “main” and to rule out that this might be a built-in tax. I renaimed the menu to something like “zorg” and ended up with a menu entry zorg and a link to {baseURL}/zorg.html where a file doesn’t exist obviously.

Did I miss something or is this a unwanted(?) behaviour of hugo?

I am still struggling with this in Hugo Static Site Generator v0.30.2 linux/amd64 BuildDate: 2017-10-19T13:34:27+02:00