How can I manage app notifications on iPhone 11?

Hello, i am a volunteer firefighter. I have an app, ( I Am Responding) on my phone that alerts me to an emergency call. I respind on the app to allow others to see who is responding to the call. Me and my wife have I Phone 11’s. Each phone has its own Apple ID. I have the i am responding app on both of our phones. We use my login credentials on both phones for the app. I only get emergency alerts on one phone, and not consistently the same phone. After speaking to (I Am responding), they said its acceptable to be used on multiple devices with same login. On the app setup, only 1 of the i phones ate visible. They said somehow, the 2 phones are being synced and only allowing the app to work on 1 phone. I checked and each phone is on its own Apple ID, and there are no other devices shown as being synced to my phone. This is the only conflict, as far as apps that this phone has. Anybody know what or where else i can check ? Thank you

stev********k@gmail.com

[Edited by Moderator]