After ZBX-11426 is implemented, there is no guarantee that events and problems will be deleted from database when events expire.

Possible case is that trigger is deleted, housekeeper is executed to clear problems for this trigger, however trigger still stays in cache and can generate new problems for some time.

Those problems then will never be deleted from database.

Note that similar problem exists for history, since new history will be added while item remain in cache and this can be after housekeeper was executed. But still history will be cleared after max storage period while events will no longer be cleared.