XmlSerializer does not deserialize XmlAttributes with a Namespace-Prefix. Bug? [duplicate]

I am trying to deserialize a given piece of XML that looks like this:

<?xml version="1.0" encoding="utf-8"?>
<tst:myRootElement xmlns:tst="myGivenNamespace">
  <tst:myList>
    <tst:myListItem>      
        <tst:myElementName tst:value="element1" />            
    </tst:myListItem>
    <tst:myListItem>      
        <tst:myElementName tst:value="element2" />            
    </tst:myListItem>
  </tst:myList>
</tst:myRootElement>

My classes (VS 2022 professional, target-framework .NET 8.0):

public static class Namespaces
{
    public const string tst = "myGivenNamespace";        
}

[XmlRoot("myRootElement", Namespace = Namespaces.tst)]
public class MyRootElement
{
    [XmlArray("myList"), XmlArrayItem(typeof(MyListItem), Namespace = Namespaces.tst)]        
    public List<MyListItem>? MyList { get; set; }
}    

[XmlRoot("myListItem", Namespace = Namespaces.tst)]
public class MyListItem
{
    [XmlElement("myElementName", Namespace = Namespaces.tst)]
    public MyElementName? ElementName { get; set; }
}

[XmlRoot("myElementName", Namespace = Namespaces.tst)]
public class MyElementName
{
    [XmlAttribute("value", Namespace = Namespaces.tst)]        
    public string? Value { get; set; }
}

My code for serialization and deserialization:

var namespaces = new XmlSerializerNamespaces();
namespaces.Add("tst", "myGivenNamespace");
var serializer = new XmlSerializer(typeof(MyRootElement));

var root1 = new MyRootElement();
root1.MyList = new List<MyListItem>();
root1.MyList.Add(new MyListItem { ElementName = new MyElementName { Value = "element1" } });
root1.MyList.Add(new MyListItem { ElementName = new MyElementName { Value = "element2" } });

// serialization
using (var fstream = new FileStream(@"c:\temp\serializertestOut.xml", FileMode.Create))
{
    serializer.Serialize(fstream, root1, namespaces);
}

// deserialization
MyRootElement? root2 = null;            
using (var fstream = new FileStream(@"c:\temp\serializertestIn.xml", FileMode.Open))
{
    root2 = (MyRootElement?)serializer.Deserialize(fstream);
}

MyRootElement? root3 = null;
using (var fstream = new FileStream(@"c:\temp\serializertestOut.xml", FileMode.Open))
{
    root3 = (MyRootElement?)serializer.Deserialize(fstream);
}

What happens when I run this code is:

• root1 is serialized to this:

  <?xml version="1.0" encoding="utf-8"?>
  <tst:myRootElement xmlns:tst="myGivenNamespace">
     <tst:myList>
       <tst:MyListItem>
         <tst:myElementName value="element1" />
       </tst:MyListItem>
       <tst:MyListItem>
         <tst:myElementName value="element2" />
       </tst:MyListItem>
     </tst:myList>
  </tst:myRootElement>
  

  Note the missing tst:-prefix of the XmlAttribute value.

• root2 is created as a MyRootElement-Instance with an empty list of MyListElements.

• root3 is created correctly, as expected, since it gets the formerly created XML from the serializer as input.

So, is there something wrong with my code? Or is there a bug in XmlSerializer, and if so, is there a way to work around this?