DESCRIBE THE ISSUE IN DETAIL: Having multiple tasks/dirs contributing META-INF/proguard directories appears to break BundleLibraryClassesInputs

STEPS TO REPRODUCE:

Enable KSP and Kapt in a project
Add some auto-value-moshi classes for kapt code gen and plain kotlin data classes using @JsonClass(generateAdapter = true) for use with moshi-ksp code gen
Run the bundleLibRuntimeToDirRelease task and observe this failure

[2021-08-28T01:45:53.750Z] FAILURE: Build failed with an exception.

[2021-08-28T01:45:53.750Z] 

[2021-08-28T01:45:53.750Z] * What went wrong:

[2021-08-28T01:45:53.750Z] Execution failed for task ':libraries:model:bundleLibRuntimeToDirRelease'.

[2021-08-28T01:45:53.750Z] > A failure occurred while executing com.android.build.gradle.internal.tasks.BundleLibraryClassesWorkAction

[2021-08-28T01:45:53.750Z]    > /mnt/tmp/android-dev/libraries/model/build/intermediates/runtime_library_classes_dir/release/META-INF/proguard

...

[2021-08-28T01:45:53.760Z] Caused by: java.nio.file.DirectoryNotEmptyException: /mnt/tmp/android-dev/libraries/model/build/intermediates/runtime_library_classes_dir/release/META-INF/proguard

[2021-08-28T01:45:53.760Z] 	at com.android.utils.FileUtils.copyFile(FileUtils.java:151)

[2021-08-28T01:45:53.760Z] 	at com.android.utils.FileUtils.copyFile(FileUtils.java:133)

[2021-08-28T01:45:53.761Z] 	at com.android.utils.FileUtils.copyFile(FileUtils.java:116)

[2021-08-28T01:45:53.761Z] 	at com.android.build.gradle.internal.tasks.BundleLibraryClassesWorkAction.copyFilesNonIncrementally(BundleLibraryClasses.kt:372)

[2021-08-28T01:45:53.761Z] 	at com.android.build.gradle.internal.tasks.BundleLibraryClassesWorkAction.run(BundleLibraryClasses.kt:315)

[2021-08-28T01:45:53.761Z] 	at com.android.build.gradle.internal.profile.ProfileAwareWorkAction.execute(ProfileAwareWorkAction.kt:74)

In some testing with Ivan to print the classes property in a doFirst block

build/intermediates/javac/release/classes - no META-INF/proguard dir
build/tmp/kotlin-classes/release - no, only containing a META-INF/... .kotlin_module  file
build/tmp/kapt3/classes/release - yes, containing generated proguard files for moshi
build/generated/ksp/release/resources - yes, containing generated proguard files for moshi

the build/intermediates/runtime_library_classes_dir/release/META-INF/proguard dir it's complaining about not being empty only contains the kapt-generated proguard files though, interestingly. This is also the case without KSP too (not empty)

Studio Build: N/A
Version of Gradle Plugin: 7.0.2
Version of Gradle: 7.2
Version of Java: 16.0.3
OS: macOS Big Sur