I am getting the following exception while removing/disabling a Drool Validation Rule, using Drools Version 5.4.0.FINAL
i.e when I call - knowledgeBase.removeRule("pkg.trade", "2.8.I23");

java.util.NoSuchElementException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:980)
at java.util.HashMap$EntryIterator.next(HashMap.java:1018)
at java.util.HashMap$EntryIterator.next(HashMap.java:1016)
at org.drools.reteoo.EvalConditionNode.doRemove(EvalConditionNode.java:302)
at org.drools.common.BaseNode.remove(BaseNode.java:109)
at org.drools.reteoo.FromNode.doRemove(FromNode.java:440)
at org.drools.common.BaseNode.remove(BaseNode.java:109)
at org.drools.reteoo.RightInputAdapterNode.doRemove(RightInputAdapterNode.java:285)
at org.drools.common.BaseNode.remove(BaseNode.java:109)
at org.drools.reteoo.BetaNode.doRemove(BetaNode.java:499)
at org.drools.common.BaseNode.remove(BaseNode.java:109)
at org.drools.reteoo.RuleTerminalNode.doRemove(RuleTerminalNode.java:358)
at org.drools.common.BaseNode.remove(BaseNode.java:109)
at org.drools.reteoo.ReteooBuilder.removeRule(ReteooBuilder.java:261)
at org.drools.reteoo.ReteooRuleBase.removeRule(ReteooRuleBase.java:460)
at org.drools.common.AbstractRuleBase.removeRule(AbstractRuleBase.java:1107)
at org.drools.common.AbstractRuleBase.removeRule(AbstractRuleBase.java:1085)
at org.drools.impl.KnowledgeBaseImpl.removeRule(KnowledgeBaseImpl.java:210)

Here is the Rule:
package pkg.trade;
rule "2.8.I23"
when
$trade : Trade()
$trdDeskId : Id() from mediator.getTradingDeskId($trade)
eval(isPositiveId($trdDeskId))
eval($trdDeskId != null && !mediator.isValidTradingDesk($trdDeskId))
then
raiseException(kcontext, $trade, "tradingDeskId", stringValue($trdDeskId));
end