When I try to see code coverage, Android Studio fails with an exception

When I run my Unit Tests in Intellij IDEA CE 2019.1 or Android Studio 3.5 to check my code coverage, when the tests end and the coverage report is about to be displayed, I get a popup telling me that my project class files are out of date and project needs recompiling. Canceling closes the coverage view. On IntelliJ, the popup shows a second time if I accept it and no coverage data is displayed. On Android Studio, accepting leads to the report. But when clicking on one of the classes in the report to see the actual coverage in the file, a stacktrace appears in the message console:

Error:Internal error: (java.lang.ClassNotFoundException) com.google.wireless.android.sdk.stats.IntellijIndexingStats$Index
java.lang.ClassNotFoundException: com.google.wireless.android.sdk.stats.IntellijIndexingStats$Index
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at com.intellij.util.indexing.counters.IndexCounters.(IndexCounters.java:34)
at com.intellij.util.indexing.impl.MapReduceIndex.(MapReduceIndex.java:85)
at org.jetbrains.jps.backwardRefs.index.CompilerReferenceIndex$CompilerMapReduceIndex.(CompilerReferenceIndex.java:232)
at org.jetbrains.jps.backwardRefs.index.CompilerReferenceIndex.(CompilerReferenceIndex.java:79)
at org.jetbrains.jps.backwardRefs.JavaCompilerBackwardReferenceIndex.(JavaCompilerBackwardReferenceIndex.java:12)
at org.jetbrains.jps.backwardRefs.JavaBackwardReferenceIndexWriter.initialize(JavaBackwardReferenceIndexWriter.java:79)
at org.jetbrains.jps.incremental.java.JavaBuilder.buildStarted(JavaBuilder.java:148)
at org.jetbrains.jps.incremental.IncProjectBuilder.runBuild(IncProjectBuilder.java:363)
at org.jetbrains.jps.incremental.IncProjectBuilder.build(IncProjectBuilder.java:178)
at org.jetbrains.jps.cmdline.BuildRunner.runBuild(BuildRunner.java:139)
at org.jetbrains.jps.cmdline.BuildSession.runBuild(BuildSession.java:302)
at org.jetbrains.jps.cmdline.BuildSession.run(BuildSession.java:135)
at org.jetbrains.jps.cmdline.BuildMain$MyMessageHandler.lambda$channelRead0$0(BuildMain.java:228)
at org.jetbrains.jps.service.impl.SharedThreadPoolImpl.lambda$executeOnPooledThread$0(SharedThreadPoolImpl.java:42)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

And I can't visualize what is covered or not.

My project is available on github: https://github.com/speekha/httpmocker. Tests are in the "tests" module.