No SHACL SQPARQL Variables in SHACL Message Supported

Hi,

I would like to display variables form SHACL SPARQL query in sh:message.

With other environments, I could do so by putting SHACL SPARQL variables in {}-brackets. Why is it not working within Stardog? How can I display variables in SHACL messages in Stardog?

Thank you for the support.

Example SHACL code:

<http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#CostsRuleShapeIII> a sh:NodeShape ;
    sh:severity sh:Info ;
    sh:targetClass <http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#Teacher> ;
    sh:sparql [
        a sh:SPARQLConstraint ;
        sh:message "{?student} is a student that gets teached." ;
        sh:prefixes [
            sh:declare [
                sh:namespace "http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#"^^xsd:anyURI ;
                sh:prefix "maic"
            ]
        ] ;
        sh:select """
  SELECT $this ?student
  WHERE {
  $this maic:teaches ?student
  }"""
    ] .

<http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#Teacher> a owl:Class ;
    rdfs:subClassOf <http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#Person> .

Example validation result:

_:bnode_3a94ee23_fce8_4cd6_817d_d02f2ed6c433_162 a sh:ValidationReport ;
   sh:conforms false .
_:bnode_3a94ee23_fce8_4cd6_817d_d02f2ed6c433_163 a sh:ValidationResult ;
   sh:resultSeverity sh:Info ;
   sh:sourceShape <http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#CostsRuleShapeIII> ;
   sh:sourceConstraint _:bnode_3a94ee23_fce8_4cd6_817d_d02f2ed6c433_159 ;
   sh:sourceConstraintComponent sh:SPARQLConstraintComponent ;
   sh:focusNode <http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#Elia> ;
   sh:value <http://www.semanticweb.org/florianschmid/ontologies/2022/0/untitled-ontology-60#Elia> ;
   sh:resultMessage "{?student} is a student that gets teached." .
_:bnode_3a94ee23_fce8_4cd6_817d_d02f2ed6c433_162 sh:result _:bnode_3a94ee23_fce8_4cd6_817d_d02f2ed6c433_163 .

Expected validation result:

sh:resultMessage "Flo is a student that gets teached." .