Having a shared Query Node as last node of a segment causes a NPE

Having a shared Query Node as last node of a segment causes a NPE as in the following test case

    @Test
    public void testSharedQueryNode() throws Exception {
        String drl =
                "query find( Integer $i, String $s )\n" +
                "    $i := Integer( toString() == $s )\n" +
                "end\n" +
                "\n" +
                "rule R2 salience -1 when\n" +
                "    $s : String()\n" +
                "    ?find( i, $s; )\n" +
                "then\n" +
                "end\n" +
                "rule R1 when\n" +
                "    $s : String()\n" +
                "    ?find( i, $s; )\n" +
                "    $i : Integer( this == 1 ) from i\n" +
                "then\n" +
                "    delete( $s );\n" +
                "end\n";

        KieHelper helper = new KieHelper();
        helper.addContent( drl, ResourceType.DRL );
        KieSession ksession = helper.build().newKieSession();

        ksession.insert("1");
        ksession.insert(1);
        ksession.fireAllRules();
    }

causes a NullPointerException like:

java.lang.NullPointerException
at org.drools.core.common.LeftTupleSetsImpl.removeInsert(LeftTupleSetsImpl.java:136)
at org.drools.core.phreak.RuleNetworkEvaluator.deleteLeftChild(RuleNetworkEvaluator.java:754)
at org.drools.core.phreak.PhreakQueryNode.doLeftDeletes(PhreakQueryNode.java:175)
at org.drools.core.phreak.PhreakQueryNode.doNode(PhreakQueryNode.java:31)
at org.drools.core.phreak.RuleNetworkEvaluator.evalQueryNode(RuleNetworkEvaluator.java:464)
at org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:353)
at org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:161)
at org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:116)
at org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:216)
at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:91)
at org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:964)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1234)