User 1234qwer1234qwer4 from ru.wikipedia reports that his notification is only partially displayed.
Notification that have been seen before and then periodically removed. User registered and received notification earlier than January.
2016-03-08 he saw the messages only after 2016-01-20 (it is at the end, after you press the big blue button at the bottom of special:notification)
2016-03-09 he saw the messages only after 2016-01-26
In settings/notification all the checkboxes for web-notifications are included and have not been changed
but here I tried 2016-03-10 to send him five consecutive ping-notifications
before the test. can be seen that the last date 2016-01-27
this is after. It can be seen that the last date 2016-01-11 - some notifications appeared
but after thanks-notification again another date 2016-01-13