XmlReader does not find a DTD file when ruinning in Azure Function

I have class which deserializes a piece of xml.

    public static TypeToDeserilize ReadFromStream(Stream stream)
    {
        using var xmlReader = XmlReader.Create(stream, new XmlReaderSettings
        {
            XmlResolver = new XmlUrlResolver(),
            ValidationType = ValidationType.DTD,
            DtdProcessing = DtdProcessing.Parse,
            IgnoreWhitespace = true
        });

        var xmlSerializer = new XmlSerializer(typeof(TypeToDeserilize));

        return (TypeToDeserilize)xmlSerializer.Deserialize(xmlReader);
    }

The given Xml contains a reference to a DTD file:
<!DOCTYPE questestinterop SYSTEM "ims_qtiasiv1p2.dtd">

When running in a Web Application it works fine, but when executed in Azure Function App I get error:

Exception while executing function: Convert There is an error in XML document (0, 0). An error has occurred while opening external DTD 'file:///C:/Program Files (x86)/SiteExtensions/Functions/4.24.3/64bit/ims_qtiasiv1p2.dtd': Could not find file 'C:\Program Files (x86)\SiteExtensions\Functions\4.24.3\64bit\ims_qtiasiv1p2.dtd'. Could not find file 'C:\Program Files (x86)\SiteExtensions\Functions\4.24.3\64bit\ims_qtiasiv1p2.dtd'.

I deploy this file into "C:\home\site\wwwroot" but it looks that XmlUrlResolver doesn't look for this file there.

As a workaround I wrote my own xml resolver class and use FunctionAppDirectory from execution context of my
Azure function.