Crashlytics plugin not uploading mapping file – Twitter API

I’ve refactored my project separating functionality into library modules in order to support Instant Apps. Everthing works great but I’m not able to see the deobfuscated stack trace at Crashlytics’s issue detail of my installed application like I was seeing before. I’m using the Fabric gradle plugin v1.24.5 and I have the following line in the base module gradle file:

apply plugin: 'com.android.feature'

Am I missing something?

EDIT:

Thanks to @Alexizamerican, I found the Crashlytics log at “~/Library/Caches/com.crashlytics/com.crashlytics.tools/” and there isn’t any reference to the mapping file:

2017-11-28 09:30:47.855 [DEBUG] (Task worker for ':') com.crashlytics  - Invoked Crashlytics Developer Tools with arguments: 
-injectableManifest true
-androidBaseManifest /Users/sirkuryaki/AndroidStudioProjects/Yop/app/src/main/AndroidManifest.xml
-buildEvent true
-androidManifest /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/intermediates/manifests/aapt/prod/release/AndroidManifest.xml
-apiSecret **XXX**
-generateResourceFile true
-tool io.fabric.tools.gradle
-version 1.24.5
-properties /Users/sirkuryaki/AndroidStudioProjects/Yop/app/crashlytics.properties
-twitterPluginId **XXX**
-buildId **XXX**
-targetResValueDir /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/generated/fabric/res/prod/release
-projectPath /Users/sirkuryaki/AndroidStudioProjects/Yop/app
-androidRes /Users/sirkuryaki/AndroidStudioProjects/Yop/app/src/main/res
-androidAssets /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/intermediates/bundles/prodRelease/assets
2017-11-28 09:30:47.939 [DEBUG] (Task worker for ':') com.crashlytics  - apiKey is **XXX**
2017-11-28 09:30:47.997 [DEBUG] (Task worker for ':') com.crashlytics  - Generating crashlytics resources
2017-11-28 09:30:47.998 [DEBUG] (Task worker for ':') com.crashlytics  - Generating build info into assets folder: /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/intermediates/bundles/prodRelease/assets
2017-11-28 09:30:48.001 [DEBUG] (Task worker for ':') com.crashlytics  - Updating build properties at: /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/intermediates/bundles/prodRelease/assets/crashlytics-build.properties
2017-11-28 09:30:48.004 [DEBUG] (Task worker for ':') com.crashlytics  - Set build id to **XXX**
2017-11-28 09:30:48.014 [DEBUG] (Build Event Notification) com.crashlytics  - Build Event: **XXX** ID:**XXX** ApiKey:**XXX** Tool:io.fabric.tools.gradle 1.24.5 Base Package Name:com.yopapp.yop Twitter Client Application Id:**XXX** API Secret Null? false Extra Details:[null]
2017-11-28 09:30:49.982 [DEBUG] (Build Event Notification) com.crashlytics  - REQUEST: https://api.crashlytics.com/spi/v1/platforms/android/apps/com.yopapp.yop/built
2017-11-28 09:30:56.789 [DEBUG] (Build Event Notification) com.crashlytics  - POST response: [reqId=**XXX**] 200

But if I look at previous builds I can see the following lines:

-storeDeobs /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/outputs/mapping/prod/release/mapping.txt
2017-10-02 13:14:45.416 [DEBUG] (Daemon worker Thread 4) com.crashlytics  - Caching deobfuscation file
2017-10-02 13:14:45.417 [DEBUG] (Daemon worker Thread 4) com.crashlytics  - Saving deobfuscation file: /Users/sirkuryaki/AndroidStudioProjects/Yop/app/build/outputs/mapping/prod/release/mapping.txt
2017-10-02 13:14:45.417 [DEBUG] (Daemon worker Thread 4) com.crashlytics  - Crashlytics is caching deobs file at /Users/sirkuryaki/Library/Caches/com.crashlytics/com.crashlytics.tools/app-**XXX**/deobs/**XXX**zip