A helper method in the Crashlytics plugin recordFlutterError(FlutterErrorDetails) passes the context of its argument as dynamic reason, where toString is called (#L125).

I believe the bug is in assertions.dart, where the various _ErrorDiagnostic subclasses spend some effort at nice formatting.

In the screenshot below (Firebase Crashlytics dashboard), I expect to see the message value, instead of Instance of 'ErrorDescription'.

Flutter version: 3.0.2 stable