UMLR — MultiplicityElement.isOrdered: Abstract Syntax Metamodel does not match the specification document

According to the UML 2.5.1, the default value for attribute isOrdered of abstract class MultiplicityElement is false, see clause 7.8.8.5 and see figure 7.10 in clause 7.5.2.

However, this default value for isOrdered is not present in the Abstract Syntax Metamodel (the XMI file with file id ptc/18-01-01 present at https://www.omg.org/spec/UML/20161101/UML.xmi). In comparison, the default value for isUnique (true) is present in the XMI. See lines 12855-12873.

<ownedAttribute xmi:type="uml:Property" xmi:id="MultiplicityElement-isOrdered" name="isOrdered">
<type href="http://www.omg.org/spec/UML/20131001/PrimitiveTypes.xmi#Boolean"/>
<ownedComment xmi:type="uml:Comment" xmi:id="MultiplicityElement-isOrdered-_ownedComment.0"
body="For a multivalued multiplicity, this attribute specifies whether the values in an instantiation of this MultiplicityElement are sequentially ordered.">
<annotatedElement xmi:idref="MultiplicityElement-isOrdered"/>
</ownedComment>
<defaultValue xmi:type="uml:LiteralBoolean"
xmi:id="MultiplicityElement-isOrdered-_defaultValue"/>
</ownedAttribute>
<ownedAttribute xmi:type="uml:Property" xmi:id="MultiplicityElement-isUnique" name="isUnique">
<type href="http://www.omg.org/spec/UML/20131001/PrimitiveTypes.xmi#Boolean"/>
<ownedComment xmi:type="uml:Comment" xmi:id="MultiplicityElement-isUnique-_ownedComment.0"
body="For a multivalued multiplicity, this attributes specifies whether the values in an instantiation of this MultiplicityElement are unique.">
<annotatedElement xmi:idref="MultiplicityElement-isUnique"/>
</ownedComment>
<defaultValue xmi:type="uml:LiteralBoolean"
xmi:id="MultiplicityElement-isUnique-_defaultValue"
value="true"/>
</ownedAttribute>

The result of this is that when I create custom diagrams illustrating specific parts from the UML metamodel, the default value for isOrdered is not shown in my UML tool.