Disconnect between alarm and SNS topic

Hi all,

I'm having difficulty figuring out the relationship between an alarm being raised and a topic picking that up. I have an already existing topic that receives a notification from an alarm but when I added more metric filters in the same namespace, none of the other ones are being received by the topic.

I confirmed separately that the alarm and the topic is working. Is there a common area that I must be missing? Is there an issue with having multiple filters all being saved to the same namespace?