Still complaining, mimicking another section

src/main/plugin/iso19139.MERIDIAN/index-fields/index.xsl

@@ -966,8 +966,13 @@
           
           <xsl:for-each select="./gmi:citation/gmd:CI_Citation/gmd:date/gmd:CI_Date[gmd:date/*/text() != '' and
                                 matches(gmd:date/*/text(), '[0-9]{4}.*')]">
-            <operationDateType><xsl:value-of select="string(gmd:dateType[1]/gmd:CI_DateTypeCode)"/></operationDateType>
-            <operationDate><xsl:value-of select="string(gmd:date[1]/gco:Date|gmd:date[1]/gco:DateTime)"/></operationDate>            
+            <xsl:variable name="dateType"
+                          select="gmd:dateType[1]/gmd:CI_DateTypeCode[text()]"
+                          as="xs:string?"/>
+            <xsl:variable name="date"
+                          select="string(gmd:date[1]/gco:Date|gmd:date[1]/gco:DateTime)"/>
+            <operationDateType><xsl:value-of select="$dateType"/></operationDateType>
+            <operationDate><xsl:value-of select="$date"/></operationDate>            
           </xsl:for-each>
           
           <xsl:apply-templates mode="index-contact" select="gmi:citation/gmd:CI_Citation/gmd:citedResponsibleParty">