Minimal demonstration of failure to inherit label when substitute elements are in a conditional.

edited-book.csl

<rdf:RDF
 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 xmlns:res="http://purl.org/vocab/resourcelist/schema#"
 xmlns:z="http://www.zotero.org/namespaces/export#"
 xmlns:dcterms="http://purl.org/dc/terms/"
 xmlns:address="http://schemas.talis.com/2005/address/schema#"
 xmlns:foaf="http://xmlns.com/foaf/0.1/"
 xmlns:bibo="http://purl.org/ontology/bibo/">
    <z:UserItem rdf:about="http://zotero.org/users/2433/items/7WJAW3IE">
        <res:resource rdf:resource="urn:isbn:978-0-19-920648-3"/>
        <z:repository>Open WorldCat</z:repository>
    </z:UserItem>
    <bibo:Book rdf:about="urn:isbn:978-0-19-920648-3">
        <dcterms:publisher>
            <foaf:Organization>
                <address:localityName>Oxford and New York</address:localityName>
                <foaf:name>Oxford University Press</foaf:name>
            </foaf:Organization>
        </dcterms:publisher>
        <bibo:isbn13>978-0-19-920648-3</bibo:isbn13>
        <dcterms:date>2007</dcterms:date>
        <dcterms:language>en</dcterms:language>
        <dcterms:title>Beyond varieties of capitalism : Conflict, contradiction, and complementarities in the European economy</dcterms:title>
        <bibo:shortTitle>Beyond varieties of capitalism</bibo:shortTitle>
        <bibo:editor rdf:nodeID="n2"/>
        <bibo:editorList>
            <rdf:Seq>
                <rdf:li rdf:nodeID="n2"/>
                <rdf:li rdf:nodeID="n4"/>
                <rdf:li rdf:nodeID="n5"/>
            </rdf:Seq>
        </bibo:editorList>
        <bibo:editor rdf:nodeID="n4"/>
        <bibo:editor rdf:nodeID="n5"/>
    </bibo:Book>
    <foaf:Person rdf:nodeID="n2">
       <foaf:givenname>Bob</foaf:givenname><foaf:surname>Hancké</foaf:surname>
    </foaf:Person>
    <foaf:Person rdf:nodeID="n4">
       <foaf:givenname>Martin</foaf:givenname><foaf:surname>Rhodes</foaf:surname>
    </foaf:Person>
    <foaf:Person rdf:nodeID="n5">
       <foaf:givenname>Mark</foaf:givenname><foaf:surname>Thatcher</foaf:surname>
    </foaf:Person>
</rdf:RDF>

substitute.csl

<?xml version="1.0" encoding="utf-8"?>
<style xmlns="http://purl.org/net/xbiblio/csl" class="note" version="1.0" demote-non-dropping-particle="sort-only">
  <info>
    <title>Substitute Failure</title>
    <id>http://www.zotero.org/styles/substitute</id>
    <link href="http://www.zotero.org/styles/substitute" rel="self"/>
    <author>
      <name>Sebastian Karcher</name>
    </author>
    <updated>2016-02-03T17:41:02+00:00</updated>
    <rights license="http://creativecommons.org/licenses/by-sa/3.0/">This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License</rights>
  </info>
<macro name="author">
<names variable="author">
<name/>
<label form="short" prefix=", "/>
<substitute>
<choose>
<if type="book">
<names variable="editor"/>
</if>
</choose>
<text variable="title"/>
</substitute>
</names>
</macro>
  <citation et-al-min="3" et-al-use-first="1" disambiguate-add-names="true">
    <layout delimiter="; " suffix=".">
<text macro="author"/> 
   </layout>
  </citation>
</style>