Here is my email sign in method in my FirebaseAuthService class:
@override
Future<UserCustom> signInWithEmail(
String emailAddress, String password) async {
try {
UserCredential _signInWithEmailAndPasswordGoogle = await _auth
.signInWithEmailAndPassword(email: emailAddress, password: password);
if (_signInWithEmailAndPasswordGoogle.user != null) {
return _userToUserModel(_signInWithEmailAndPasswordGoogle.user);
} else {
throw PlatformException(
code: 'SIGN_IN_INTERRUPTED', message: 'Sin in interrupted');
}
} on PlatformException {
print('Happened');
rethrow;
}
}
And here is where the exception should be handled:
// creating the submit function
Future<void> _submit(EmailSignInModelProviderPattern model) async {
// if it is on sign in use sign in function ELSE use register function
try {
await model.submit();
Navigator.pop(context);
} on PlatformException catch (e) {
CustomErrorPlatformException(
title: 'Sign in failed',
exception: e,
).show(context);
} catch(e){
print(e.toString());
}
}
And yet when I enter a badly formatted address the process is interrupted at message_codecs.dart file at the method dynamic decodeEnvelope(ByteData envelope){... line 572 with error message: 
Exception has occurred. PlatformException (PlatformException(firebase_auth, com.google.firebase.auth.FirebaseAuthInvalidCredentialsException: The email address is badly formatted., {code: invalid-email, additionalData: {}, message: The email address is badly formatted.}))
I couldn't figure out how to handle this exception, knowing that it never happened to me before upgrading to firebase_auth: ^0.18.0+1.