Hello Ravi ,
I suggest you check the rule set thoroughly , the event handler status will be updated via rule set , there will be step which checks posting of particular event in event management eg .
If Event - " Shipment Departed" is Reported ,
If Yes --> Change Event Handler Status to " Departed"
Check if your rule set has any such events or actions linked to updation of event handler status.
You can check the standard rule set for shipment scenario to understand the updation better.
Regards,
Arun Yesodharan