Execute callback function into ionic fcm onNotification

Hello friends, when trying to call a function that is in the same ts file, within onNotification, it does not update the data until some action happens, example opened the menu

I attach images of examples

I need that when receiving a notification in foreground the data of a label is changed, in this case I only do it with an input or a checkbox to show the example

code constructor

this.fcm.onNotification().subscribe(data => {
            if(data.wasTapped){
                console.log("Received in background");
            } else {
                 console.log("Received in foreground");
                 this.callback();
            };
        });

I attach example images of the process

app example
PNG

send notification from fcm

Notification is received but no changes occur when you open the menu for example, change the interface
PNG

and when you close the menu the interface changes

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Any suggestions? thanks!!