[rules-users] Inconsistent behavior between LHS and RHS ...

Hi, I've been using drools 4.07 for a while. I have found a weird case. It seems that when evaluating the LHS some fact is true but the RHS probes it wasn't actually true. The example code is at the end. It is very weird to me I have no clue about how to solve this or what could be happening! rule "A-Rule" no-loop true ruleflow-group "validate-task" salience -9999999 when then "+$task.getTechnicalParams().get(0).getName()); "+$task.getTechnicalParams().get(1).getName()); "+$task.getParameter("PRIMARYDNS")); end further explanation: The Task class has a List<Parameter> technicalParams, originally the eval part was: not(Parameter (name=="PRIMARYDNS") from $task.technicalParams()) it didn't work and I coded this "getParameter" method just to make some tests. So, it seems the collection appears "empty" to the LHS but in fact it isnt! any clue? thanks a lot, Javier