Incoming admin events increased

[passuff]

As soon as I start wiffi-wz the incoming events of admin adapter increase by 150. This will cause the admin web interface to not update the states anymore:

Admin.0 Unsubscribe from all states, except system's, because over 3 seconds the number of events is over 200 (in last second 0)

I'm using two devices (Weatherman and Rainyman) which have less than 80 states. I've other adapters with way more states causing less stress for the admin interface so I really wonder what causes this stress?
You can directly feel the difference on the web interface performance with wiffi-wz instance turned on or off...