[Saxon-JS 2] Callback template param value

Hi,

I don't get how this happens -- why is the same param value passed to
the callback template when I would expect 3 different values?

<xsl:template>
    ...
    <xsl:variable name="facet-bgps"
select="$select-xml//json:map[json:string[@key = 'type'] =
'bgp']/json:array[@key =
'triples']/json:map[not(starts-with(json:string[@key = 'predicate'],
'?'))][starts-with(json:string[@key = 'object'], '?')]"
as="element()*"/>
    <xsl:for-each select="$facet-bgps">
        <xsl:sort select="ac:property-label(json:string[@key = 'predicate'])"/>
        <xsl:variable name="bgp" select="." as="element()"/>
        ...
        <xsl:variable name="results-uri" select="..." as="xs:anyURI"/>

        <xsl:message>
        PREDICATE: <xsl:value-of select="$bgp/json:string[@key = 'predicate']"/>
        </xsl:message>

        <ixsl:schedule-action http-request="map{ 'method': 'GET',
'href': $results-uri, 'headers': map{ 'Accept':
'application/sparql-results+xml' } }">
            <xsl:call-template name="onFacetValueResultsLoad">
                <xsl:with-param name="container-id" select="$container-id"/>
                <xsl:with-param name="bgp" select="$bgp"/>
            </xsl:call-template>
        </ixsl:schedule-action>
    </xsl:for-each>
</xsl:template>

<xsl:template name="onFacetValueResultsLoad">
    <xsl:context-item as="map(*)" use="required"/>
    <xsl:param name="container-id" as="xs:string"/>
    <xsl:param name="bgp" as="element()"/>

    <xsl:message>
    PREDICATE IN CALLBACK: <xsl:value-of select="$bgp/json:string[@key
= 'predicate']"/>
    </xsl:message>
    ...

This is the output I get:

xsl:message:
            PREDICATE: http://purl.uniprot.org/core/organism
xsl:message:
            PREDICATE: http://purl.uniprot.org/core/encodedBy
xsl:message:
            PREDICATE: http://www.w3.org/2000/01/rdf-schema#label
xsl:message:
PREDICATE IN CALLBACK: http://www.w3.org/2000/01/rdf-schema#label
xsl:message:
PREDICATE IN CALLBACK: http://www.w3.org/2000/01/rdf-schema#label
xsl:message:
PREDICATE IN CALLBACK: http://www.w3.org/2000/01/rdf-schema#label

3 different values in the calling template, the same 1 value in the
callback template.
How is that possible?


Martynas