[rules-users] Bug in "not" ???

Using Drools Expert 5.0.1 The following rule fires both when the "not" is there, and also if the "not" is commented out. Clearly, both cannot be true, so there is something wrong somewhere. I've narrowed it down to the testing of the $parentEmploymentId declaration - the AccountHolder CE, which is inside the context of the "not", is referencing $parentEmploymentId, which is declared outside the "not". If the indicated line is commented out, then the expression behaves sensibly (i.e. fires either when the "not" is used, or when it isn't, but not both). However, an important business semantic element is then missing from the rule. Is this a bug in Drools, or am I misusing something? rule "RS7713.9.2_" when Employment ( $parentEmploymentId : myId ) not # if the not is commented out, the rule still fires!!!! ( AccountHolder ( $parentEmployerInfoId : myId , parentId == $parentEmploymentId # if this line is commented, it behaves sensibly (per the 'not'), but misses an important business semantic ) and BusinessName ( parentId == $parentEmployerInfoId , lines contains "DISTRESS" ) ) then ; end Tom Murphy Business Process Consultant Wells Fargo HCFG - CORE Deal Decisioning Platform 800 S. Jordan Creek Parkway | West Des Moines, IA 50266 MAC: X2301-01B Office: 515 324 4853 | Mobile: 515 423 4334 This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose, or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation.