I still get this behavior on 6.1. This seems to happen because it shows each notification immediately. Could the panel be a bit more clever and use a timed interval to check whatever the delta in notification are only from the point of inquiry and cap it to about 50 with a cursor to hint at more? That way, even if 2,000 notifications came in, it wouldn't try to display them ALL at once. And some duplication of the notification could occur with hashing of the notification's serialized form versus repeating the same thing (especially if it's the same thing over and over).