[rules-users] Why double rule activation?

[Bagwell, Allen F]

I've encountered rule engine behavior I'm knocking my head against the wall trying to figure out.  I'm a Drools newbie, so please forgive if this I am doing something bone-headed wrong.

Basically I'm inserting an object into my working memory.  The object itself has a default setting of 0.0 for a brightness value, and this setting matches the LHS condition for my first rule.  The problem is the rule activates twice for a single object insertion as described in the audit log.  It consequently executes twice when I fire all rules. Then whenever I change the value in question, any single update to the same object also causes double rule activation and execution.

The rules I've written are not complex. Here's my drl file:

package dimmerie;

#list any import classes here.

import knowledgebase.*;
import NipcLogger;

#declare any global variables here

global NipcLogger IELogger;

rule "Light is off"
        when
                $brightness : MyVariable(uniqueName == "ds1 at brightness", currentValue == 0.0)
        then
                IELogger.info("DimmerSwitch1 has no brightness value");
end

rule "Light Below 50%"
        when
                $brightness : MyVariable(uniqueName == "ds1 at brightness", currentValue < 0.50, currentValue > 0.0)
        then
                IELogger.info("DimmerSwitch1 is below 50% brightness");
end

rule "Light 50% or Above"
        when
                $brightness : MyVariable(uniqueName == "ds1 at brightness", currentValue >= 0.5)
        then
                IELogger.info("DimmerSwitch1 is at or above 50% brightness");
end

I'm hoping I've described enough without having to post additional code.  Can anyone suggest why this is happening?

Thanks,
Allen