Startup rule fired >=3x

Setup, Configuration and Use Scripts & Rules
1

I have a rule which runs when system is started on a RPI3 running OH2.0 stable.
I notice that after each reboot or restart of OH2 this rules is fired >=3x.
Below my rule (simplified)
is this a bug?

rule "System started"
when
System started
then
var Timer waitTimer = null

SystemStarting.sendCommand(ON)
logDebug("startup", "System started")

waitTimer = createTimer(now.plusMinutes(4)) [|
LichtenUit.sendCommand(OFF)
Thread::sleep(10)
LichtenAan.sendCommand(OFF)
Thread::sleep(10)
Sfeerlicht.sendCommand(OFF)
Thread::sleep(100)
SystemStarting.sendCommand(OFF)
logDebug(“startup”, “Rule System starting ended”)
logDebug(“startup”, “System is ready!”)
]
end