IntelliJ IDEA "Cannot resolve symbol 'Xxxxx'" but builds modules successfully on a Gradle project

"Cannot resolve symbol 'Xxxxx'" on a Gradle project

1. File > Invalidate Caches / Restart...
2. Invalidate
3. File > Close Project
4. Remove the Gradle project from projects history
5. Exit IntelliJ IDEA
6. Remove "IntelliJ IDEA system" dir
   

   $ rm -rf ~/.IntelliJIdea201X.Y/system/
   

7. Start IntelliJ IDEA again
8. Import the Gradle project