diff --git a/centaur/src/main/resources/standardTestCases/dedup_localizations_papi_v2.test b/centaur/src/main/resources/standardTestCases/dedup_localizations_papi_v2.test
new file mode 100644
index 00000000000..71edd6de8ea
--- /dev/null
+++ b/centaur/src/main/resources/standardTestCases/dedup_localizations_papi_v2.test
@@ -0,0 +1,13 @@
+name: dedup_localizations_papi_v2
+testFormat: workflowsuccess
+backends: [Papiv2]
+
+files {
+  workflow: dedup_localizations_papi_v2/dedup_localizations_papi_v2.wdl
+}
+
+metadata {
+  workflowName: dedup_localizations_papi_v2
+  status: Succeeded
+  "outputs.dedup_localizations_papi_v2.check_log.num_input_localizations": 1
+}
diff --git a/centaur/src/main/resources/standardTestCases/dedup_localizations_papi_v2/dedup_localizations_papi_v2.wdl b/centaur/src/main/resources/standardTestCases/dedup_localizations_papi_v2/dedup_localizations_papi_v2.wdl
new file mode 100644
index 00000000000..25ecc045fb0
--- /dev/null
+++ b/centaur/src/main/resources/standardTestCases/dedup_localizations_papi_v2/dedup_localizations_papi_v2.wdl
@@ -0,0 +1,59 @@
+version 1.0
+
+workflow dedup_localizations_papi_v2 {
+  call producer
+  call consumer { input: first = producer.data, second = producer.data }
+  call check_log { input: out_file_path = consumer.out, log_file_name = "consumer.log" }
+}
+
+task producer {
+  command {
+    echo "Here is some data." > data.txt
+  }
+
+  runtime {
+    docker: "ubuntu:latest"
+  }
+
+  output {
+    File data = "data.txt"
+  }
+}
+
+task consumer {
+  input {
+    File first
+    File second
+  }
+
+  command {
+    # noop
+  }
+
+  runtime {
+    docker: "ubuntu:latest"
+  }
+
+  output {
+    File out = stdout()
+  }
+}
+
+task check_log {
+  input {
+      String out_file_path
+      String log_file_name
+  }
+  String file_log = sub(out_file_path, "/stdout$", "/" + log_file_name)
+  command {
+      set -euo pipefail
+      gsutil cp ~{file_log} log.txt
+      set +e
+      grep 'Localizing input gs://cloud-cromwell-dev-self-cleaning/cromwell_execution/travis/dedup_localizations_papi_v2/' log.txt | grep -c "data.txt"
+  }
+  output {
+      File out = stdout()
+      Int num_input_localizations = read_int(stdout())
+  }
+  runtime { docker: "google/cloud-sdk" }
+}
diff --git a/supportedBackends/google/pipelines/v2alpha1/src/main/scala/cromwell/backend/google/pipelines/v2alpha1/PipelinesApiAsyncBackendJobExecutionActor.scala b/supportedBackends/google/pipelines/v2alpha1/src/main/scala/cromwell/backend/google/pipelines/v2alpha1/PipelinesApiAsyncBackendJobExecutionActor.scala
index 80d90c1dc7d..9cfa80a2447 100644
--- a/supportedBackends/google/pipelines/v2alpha1/src/main/scala/cromwell/backend/google/pipelines/v2alpha1/PipelinesApiAsyncBackendJobExecutionActor.scala
+++ b/supportedBackends/google/pipelines/v2alpha1/src/main/scala/cromwell/backend/google/pipelines/v2alpha1/PipelinesApiAsyncBackendJobExecutionActor.scala
@@ -70,8 +70,10 @@ class PipelinesApiAsyncBackendJobExecutionActor(standardParams: StandardAsyncExe
     }
 
     val filesByContainerParentDirectory = filesWithSameNames.groupBy(_.containerPath.parent.toString)
+    // Deduplicate any inputs since parallel localization can't deal with this.
+    val uniqueFilesByContainerParentDirectory = filesByContainerParentDirectory map { case (p, fs) => p -> fs.toSet  }
 
-    val filesWithSameNamesTransferBundles: List[String] = filesByContainerParentDirectory.toList map { case (containerParent, filesWithSameParent) =>
+    val filesWithSameNamesTransferBundles: List[String] = uniqueFilesByContainerParentDirectory.toList map { case (containerParent, filesWithSameParent) =>
       val arrayIdentifier = s"files_to_localize_" + DigestUtils.md5Hex(bucket + containerParent)
       val entries = filesWithSameParent.map(_.cloudPath) mkString("\"", "\"\n|  \"", "\"")