Crashlytics no longer uploads mapping file when using Android App Bundle

Fabric finally fixed that bug in 1.31.0

1.31.0: July 24, 2019
- Fixed mapping file uploads for Dexguard users building Android App Bundles (requires Dexguard 8.5).
- Fixed an issue which, when building Android App Bundles, caused APK builds to be triggered as well.
- Fixed an issue preventing Fabric API keys defined in a fabric.properties file from being injected properly for Android App Bundle builds.

I've faced the same problem and after updating the version it was fixed:

buildscript {
  ...
  classpath 'io.fabric.tools:gradle:1.31.0'
  ...
}

I never used App Bundle before; however, I want you to try uploading the mapping file myApp/outputs/mapping/release/mapping.txt to Play Store Console -> Android vitals -> Deobfuscation files.

Good luck!.