title: java.lang.IllegalStateException: Dex archives: setting .DEX extension only for .CLASS files
body: <p>I build the project at gitlab ci </p>
  
  <pre><code>./gradlew assembleDebug --stacktrace
  </code></pre>
  
  <p>and sometimes it throws an error:</p>
  
  <pre><code>FAILURE: Build failed with an exception.
  * What went wrong:
  Execution failed for task ':app:transformClassesWithDexBuilderForDebug'.
  &gt; com.android.build.api.transform.TransformException: java.lang.IllegalStateException: Dex archives: setting .DEX extension only for .CLASS files
  </code></pre>
  
  <p>At my local pc it works correctly.</p>
  
  <p>kotlin version is 1.2</p>
  
  <p>multidex is enabled</p>
  
  <p>What is the reason of this error?</p>