And what is your question? 
If this is something you aren't expecting: check the Alert management rules you have set up, since they are creating the incidents. Probably somewhere there isn't a check on the uniqueness of an issue. Or are it different alerts, but just related to the same incident? In that case you need to put some validation on that.

You don't ask a question, you don't provide the rules, you don't give any information about what is expected and what is not. If you want help, you will need to provide information with which we can help you.