Then, this is ok.
What happens is everytime a box uploads data to VidiCenter, VidiCenter sends back a mssage saying "ok, events inserted" and the box then deletes those events from its memory. Sometimes, the communication between the box and VidiCenter is cut before VidiCenter could say that the last few events were inserted. So the box keeps them locally. Upon the next upload, those events will be sent again. Since they are already in the database, they will be refused.