I got an event E1 that is only valid, if the latest event E2 following E1 within 2 minutes has the value 1

--> I want have the rule fire 2 minutes after E1 but only if E1 is valid

This is my rule:

rule "inform about E1"

when

	//event (T1) is the initial trigger

	$event1 : Event(type == EventType.T1)

	//there is an event (T2) with value 0 between 0,2m after doorClosed

	$event2: Event(type == EventType.T2, value == 1, this after [0, 2m] $event1, $timestamp : timestamp)

	//there is no newer event (T2) within the timeframe

	not Measurement(type == EventType.T2, this after [0, 2m] $event1, timestamp > $timestamp) 

then

	//print info

	log(drools, "E1 valid");

end

An example of Events:

12:00:00  - E1
12:01:00  - E2 ( value = 0 ) 
12:01:10  - E2 ( value = 0 ) 
12:01:40  - E2 ( value = 0 ) 
12:01:50  - E2 ( value = 1 ) 
12:02:10  - E2 ( value = 0 )

I would expect the output:   [log() does log the clock-time when my rule fires)

12:02:00 E1 valid

But what I get is:

12:03:50 E1 valid


So I see that the late coming E2 (@12:02:10) is correctly ignored, the rule result is basically correct, but the rule is fired much to late.  (actually 2 minutes after $event2 and not as expected 2 minutes after $event1).

Could someone give me a hint what I did wrong?

Regards, 
Alex