Data gets lost in Easy Profile when using eb - by: Chris

Hi

I have a Problem with Easy Profile and eventbooking.
In easy-Profile i have some extra Fields on an extra Tabs,only visible and editable for the Admin.
Then i use the eventbooking Component with its "Events Booking - Easy Profile plugin".
Everything works fine. When a user want to book an event, he can login and in the booking form are the prepopulated Data Values from the Easy-Profile Table.

But now data gets lost! From time to time all data from a specific Tab (Goup member aerea) gets lost.
This is, if a registered users signs up for an event.

How can that be?

Thank you for helping
Chris