diff --git a/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala b/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala
index a10f6880fc..800ff9fdb0 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/PhasedFusingActorMaterializer.scala
@@ -23,6 +23,7 @@ import akka.event.Logging
 import akka.event.LoggingAdapter
 import akka.stream.Attributes.InputBuffer
 import akka.stream._
+import akka.stream.impl.Stages.DefaultAttributes
 import akka.stream.impl.StreamLayout.AtomicModule
 import akka.stream.impl.fusing.ActorGraphInterpreter.ActorOutputBoundary
 import akka.stream.impl.fusing.ActorGraphInterpreter.BatchingActorInputBoundary
@@ -750,7 +751,7 @@ private final case class SavedIslandData(
     val boundary = new ActorOutputBoundary(shell, out.toString)
     logics.add(boundary)
     boundary.stageId = logics.size() - 1
-    boundary.attributes = logic.attributes
+    boundary.attributes = logic.attributes.and(DefaultAttributes.outputBoundary)
 
     val connection = outConn()
     boundary.portToConn(boundary.in.id) = connection
@@ -774,6 +775,7 @@ private final case class SavedIslandData(
       new BatchingActorInputBoundary(bufferSize, shell, publisher, connection.inOwner.toString)
     logics.add(boundary)
     boundary.stageId = logics.size() - 1
+    boundary.attributes = connection.inOwner.attributes.and(DefaultAttributes.inputBoundary)
 
     boundary.portToConn(boundary.out.id + boundary.inCount) = connection
     connection.outHandler = boundary.handlers(0).asInstanceOf[OutHandler]
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Stages.scala b/akka-stream/src/main/scala/akka/stream/impl/Stages.scala
index cf995e6202..e4c4078c3b 100755
--- a/akka-stream/src/main/scala/akka/stream/impl/Stages.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Stages.scala
@@ -142,6 +142,9 @@ import akka.stream._
     val inputStreamSink = name("inputStreamSink") and IODispatcher
     val fileSink = name("fileSink") and IODispatcher
     val fromJavaStream = name("fromJavaStream")
+
+    val inputBoundary = name("input-boundary")
+    val outputBoundary = name("output-boundary")
   }
 
 }