How to make the error title and stacktrace in firebase crashlytics readable?

Question

For my Flutter Android app, error title and stacktrace of some of the error reports are not readable as the following. Especially non fatal errors that are automatically reported.

In contrast, the stacktrace of the error reports that are manually reported using FirebaseCrashlytics.instance.recordFlutterError method and crash reports, are readable.

Here is the content of my proguard-rules.pro file.

## Flutter wrapper
 -keep class io.flutter.app.** { *; }
 -keep class io.flutter.plugin.** { *; }
 -keep class io.flutter.util.** { *; }
 -keep class io.flutter.view.** { *; }
 -keep class io.flutter.** { *; }
 -keep class io.flutter.plugins.** { *; }
 -keep class com.google.firebase.** { *; }
 -dontwarn io.flutter.embedding.**
 -ignorewarnings
 -keep class io.grpc.** { *; }