System started rule executing on its own while system running

I setup some temp setpoints in the system started rule that is quite simple:

rule "variable startup"
        System started
	logDebug("TERMO","System started initial setpoint startup!" )
	postUpdate(B_Temp_Setpoint_Bedroom, 21)
	postUpdate(B_Temp_Setpoint_Office, 23)
	postUpdate(GF_Temp_Setpoint_Living, 23)
	postUpdate(GF_Temp_Setpoint_Bedroom, 21)

But for some reason it gets executed about once in 5 minutes while the openhab is running! there is an event next to it that I do not really understand.

12:13:36.657 [DEBUG] [eclipse.smarthome.model.script.TERMO] - System started initial setpoint startup!
12:13:36.692 [INFO ] [org.quartz.core.QuartzScheduler     ] - Scheduler openHAB-job-scheduler_$_NON_CLUSTERED started.

On what version are you ( OH1or2, stable or nigthly release).
Please post the log-lines BEFORE the one from the rule.

That is nightly build #658, of OH2
Before there is absolutely nothing suspicious just a bunch of sensor updates.
I now realized that this problem has been around for quite long time as I had those unexpected changes to the setpoints for weeks, I just finaly added loging to the system started rule.

I had some issue with “system started” rules on older builds where those rules triggered whenever the rule was newly read ( I e. saved). But that seems not to be your case.

I see the rule triger when I save items file for example, but sometimes it still does that , especialy when there is high CPU load on the RPI3 I use for OH2.

Since a rule was to populate NULL variables I did add some saveguards to prevent with messing my variables on the run.

if (GF_Temp_Setpoint_Bedroom == NULL) postUpdate(GF_Temp_Setpoint_Bedroom, 21)

And will try to live with that.