Background:
Siteaccessmatcher are Map\URI with simple prefixes.

language-switch:

<a href="{{ url( 'ez_urlalias', { 'locationId' : locationId, 'siteaccess' : siteaccess }) }}" >

On all locations it works fine, create an urlalias prefixed with the correct siteaccess prefix. Only if locationId is the root node/location it creates a wrong system link like:

http://foobar.local/es/de/content/location/2

Note:

• the siteaccess prefix is twice
• instead of an url alias the system path is used

The same result if I use: all links are fine, only the root location is wrong.

<a href="{{ url( ez_route( location , { 'language' : 'fre-FR'})) }}"  >