While setting up Rules and RuleSets you may want to exclude either target types or alert categories from your notifications. Well, there’s an issue if you try to do this in OEM 13c.
If you configure a Rule that has the exclusion and contains more than one category, then you will keep receiving alerts from it. So the exclusion won’t work.
In order to fix it you need to apply a patch or the January 2018 BP for OEM.
MOS note (Doc ID 2347238.1) shall be used as a reference.