[firebase_messaging] OnBackgroundMessage does the inscrutions inside the body function in debug mode but not in release mode

[Anoirwork]

Hi there,
So i've been working on this feature where if a notification is received and the app is terminated, the end user clicks on the notifcation body :
debug mode :
- The app opens then it will redirect me to facebook using Url_launcher this is working perfectly
release mode :
- the app opens only and no instrcution had been executed
below is my code of the top level function
https://ibb.co/PGkHp2k
any help, guidance or putting me on the road would be appricated