How to view Flutter app Dart stacktrace with Firebase Crashlytics?

Question

I have a flutter app that uses some Android-specific code (Java/Kotlin). In "app/build.gradle" i do have firebaseCrashlytics/mappingFileUploadEnabled true:

    release {
            signingConfig signingConfigs.googleplaySigningConfig

            minifyEnabled true
            debuggable false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard.cfg'

            firebaseCrashlytics {
                mappingFileUploadEnabled true
                nativeSymbolUploadEnabled true
                unstrippedNativeLibsDir "build/app/intermediates/merged_native_libs/release/out/lib"
            }

            ndk {
                debugSymbolLevel 'FULL'
            }
        }

Also note in root "build.gradle":

classpath 'com.google.firebase:firebase-crashlytics-gradle:2.8.1'

I build the app using flutter build appbundle and i believe it should trigger uploading of obfuscation maps to Firebase crashlytics.

However i get smth like: which makes me think Firebase Crashlytics was unable to find deobfuscated code for obfuscated using the uploaded mapping.

What can i do or check?

PS. After reading the error message more carefully i realized it's actually Dart code where the error happens (not my Java code). However, i'm still confused why i can't see Dart stacktrace instead.