It happens as follows.
Join to a device, select "Use Notifications", select 1 or 2 notices, apply and OK.
When I enter the device again to see if everything is fine other notifications are selected than those who did not elect me.
Dude service runs on a Windows machine and I'm managing 2000 from another Windows 7.
The dude is version 4.Beta3

In this picture, I select 3 notifications, closing and re-enter appear 4

this is a Bug?

Sorry for my English

You can set notifications on per service(probe) basis, by double-clicking on the monitored service in the services tab. Maybe you have selected different notifications on the monitored services for this particular device!?