Range Index not applied to field in eXist-DB (not shown in Monex)

Question

I am not sure, if this a bug or if I'm doing something wrong (or if I'm having the wrong assumptions).

I have a collection with one document:

<test bar="baz">foo</test>

And a collection.xconf:

<collection xmlns="http://exist-db.org/collection-config/1.0">
  <index xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <range>
      <create qname="test">
        <field name="bar-attr" match="@bar" type="xs:string"/>
        </create>
    </range>
  </index>
</collection>

Now i would assume, that the Index, when viewed in Monex, for bar-attr(in the index for the collection) lists the value of @bar(here baz). If I switch my configuration to:

<collection xmlns="http://exist-db.org/collection-config/1.0">
  <index xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <range>
      <create qname="@bar"/>
    </range>
  </index>
</collection>

baz is part of the index as expected.

Now my question:

1. Are field-values not listed in the index-view in monex?
2. Or is my understanding of the fields totally wrong?

Note: I am using eXist-db 6.2.0 in a Docker-Container on an Apple Silicon based Mac. But this problems seems also to exist in instances running outside Docker on other platforms (I can reproduce it in a Linux VM).