This is due to the configuration on Amazon.
- Open Amazon EC2 console
- Click ?Instances? on the navigation pane and the appropriate instance
- Click ?Actions? and select ?Instance Settings?
- Click ?Change Shutdown Behavior?
- For Barracuda WAF instance select the ?Shutdown behavior? as stop
When the shutdown behavior is set as ?Terminate? the WAF instance will get terminated when a shutdown/hardreboot is performed.