LinqToXsd double output

Base.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="C" targetNamespace="C">
  <xs:complexType name="FirstAbstractBase" abstract="true">
    <xs:annotation>
      <xs:documentation>
        Doc, doc, doc
      </xs:documentation>
    </xs:annotation>
    <xs:sequence/>
    <xs:attribute name="echo" type="xs:string" use="optional">
      <xs:annotation>
        <xs:documentation>
          Doc, doc, doc
        </xs:documentation>
      </xs:annotation>
    </xs:attribute>
  </xs:complexType>
  <xs:complexType name="SecondAbstractBase" abstract="true">
    <xs:annotation>
      <xs:documentation>
        Doc, doc doc
      </xs:documentation>
    </xs:annotation>
    <xs:complexContent>
      <xs:extension base="FirstAbstractBase">
        <xs:sequence/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:schema>

Build.bat

LinqToXsd gen Child1.xsd,Child2.xsd -o Output -c Build.config

Build.config

<?xml version="1.0" encoding="utf-8"?>
<Configuration xmlns="http://www.microsoft.com/xml/schema/linq">
  <Namespaces>
    <Namespace DefaultVisibility="public" Schema="C" Clr="DemoNamespace" />
  </Namespaces>
  <Validation>
    <VerifyRequired>false</VerifyRequired>
  </Validation>
  <Transformation>
    <Deanonymize strict="false" />
  </Transformation>
</Configuration>

Child1.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs             = "http://www.w3.org/2001/XMLSchema"
           xmlns:core           = "C"
           xmlns                = ""
           attributeFormDefault = "qualified"
           elementFormDefault   = "qualified">
  
  <xs:import namespace      = "C"
             schemaLocation = "Base.xsd"/>
  
  <xs:include schemaLocation="Types.xsd"/>
  
  <xs:complexType name="ChildType10">
    <xs:annotation>
      <xs:documentation>
        Doc, doc, doc
      </xs:documentation>
    </xs:annotation>
    <xs:complexContent>
      <xs:extension base="core:SecondAbstractBase">
        <xs:sequence/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>  
  
  <xs:complexType name="ChildType11">
    <xs:annotation>
      <xs:appinfo>
        <asDataModeSupported>true</asDataModeSupported>
        <hssDataModeSupported>false</hssDataModeSupported>
      </xs:appinfo>
      <xs:documentation>
        Doc, doc, doc
      </xs:documentation>
    </xs:annotation>
    <xs:complexContent>
      <xs:extension base="core:SecondAbstractBase">
        <xs:sequence>
          <xs:element name="userId" type="UserId"/>
        </xs:sequence>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>  
  
</xs:schema>

Child2.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs             = "http://www.w3.org/2001/XMLSchema"
           xmlns:core           = "C"
           xmlns                = ""
           attributeFormDefault = "qualified"
           elementFormDefault   = "qualified">
  
  <xs:import namespace      = "C"
             schemaLocation = "Base.xsd"/>
  
  <xs:include schemaLocation="Types.xsd"/>
  
  <xs:complexType name="ChildType20">
    <xs:annotation>
      <xs:documentation>
        Doc, doc, doc
      </xs:documentation>
    </xs:annotation>
    <xs:complexContent>
      <xs:extension base="core:SecondAbstractBase">
        <xs:sequence/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>  
  
  <xs:complexType name="ChildType21">
    <xs:annotation>
      <xs:appinfo>
        <asDataModeSupported>true</asDataModeSupported>
        <hssDataModeSupported>false</hssDataModeSupported>
      </xs:appinfo>
      <xs:documentation>
        Doc, doc, doc
      </xs:documentation>
    </xs:annotation>
    <xs:complexContent>
      <xs:extension base="core:SecondAbstractBase">
        <xs:sequence>
          <xs:element name="userId" type="UserId"/>
        </xs:sequence>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>  
  
</xs:schema>

Types.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:core="C" attributeFormDefault="qualified" elementFormDefault="qualified">
  <xs:simpleType name="UserId">
    <xs:annotation>
      <xs:documentation>
        Doc, doc, doc
      </xs:documentation>
    </xs:annotation>
    <xs:restriction base="xs:token">
      <xs:minLength value="1"/>
      <xs:maxLength value="161"/>
    </xs:restriction>
  </xs:simpleType>
</xs:schema>