Deleted facts are still retained by ksession after ksession.delete() in BRMS

Issue

• My application uses a stateful ksession for long-time without disposing. It inserts facts, fireAllrules and deletes the facts. Then I observe that deleted facts are retained by the ksession and not garbage collected even after ksession.delete(). So the heap keeps increasing. I understand that ksession.dispose() frees all facts. But does ksession.delete() free the fact as well? My rules are like this:

rule "rule1"
    when
        $a : FactA()
        $b : FactB()
        $c : FactC(name == "Paul")
    then
        System.out.println("rule1");
end

rule "rule2"
    when
        $a : FactA()
        $b : FactB()
        $c : FactC(name == "John")
    then
        System.out.println("rule2");
end