diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/StreamRefsSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/StreamRefsSpec.scala
index 085a1584b3..c5ed6469bd 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/StreamRefsSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/StreamRefsSpec.scala
@@ -15,8 +15,9 @@ import akka.testkit.{ AkkaSpec, ImplicitSender, SocketUtil, TestKit, TestProbe }
 import akka.util.ByteString
 import com.typesafe.config._
 
+import scala.collection.immutable
 import scala.concurrent.duration._
-import scala.concurrent.Future
+import scala.concurrent.{ Await, Future }
 import scala.util.control.NoStackTrace
 
 object StreamRefsSpec {
@@ -161,6 +162,10 @@ object StreamRefsSpec {
         port = ${address.getPort}
         hostname = "${address.getHostName}"
       }
+
+      stream.materializer.stream-ref {
+        subscription-timeout = 5 seconds
+      }
     }
   """).withFallback(ConfigFactory.load())
   }
@@ -278,10 +283,11 @@ class StreamRefsSpec(config: Config) extends AkkaSpec(config) with ImplicitSende
       remoteActor ! "give-subscribe-timeout"
       val remoteSource: SourceRef[String] = expectMsgType[SourceRef[String]]
       // materialize directly and start consuming, timeout is 500ms
-      remoteSource.throttle(1, 100.millis, 1, ThrottleMode.Shaping)
-        .take(10) // 10 * 100 millis - way more than timeout for good measure
+      val eventualStrings: Future[immutable.Seq[String]] = remoteSource.throttle(1, 100.millis, 1, ThrottleMode.Shaping)
+        .take(60) // 60 * 100 millis - data flowing for 6 seconds - both 500ms and 5s timeouts should have passed
         .runWith(Sink.seq)
-        .futureValue // this would fail if it timed out
+
+      Await.result(eventualStrings, 8.seconds)
     }
   }
 
@@ -342,7 +348,7 @@ class StreamRefsSpec(config: Config) extends AkkaSpec(config) with ImplicitSende
         .run()
 
       val failure = p.expectMsgType[Failure]
-      failure.cause.getMessage should include("Remote side did not subscribe (materialize) handed out Sink reference")
+      failure.cause.getMessage should include("Remote side did not subscribe (materialize) handed out Source reference")
 
       // the local "remote sink" should cancel, since it should notice the origin target actor is dead
       probe.expectCancellation()
diff --git a/akka-stream/src/main/scala/akka/stream/impl/streamref/SinkRefImpl.scala b/akka-stream/src/main/scala/akka/stream/impl/streamref/SinkRefImpl.scala
index d824d720a3..a423636f06 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/streamref/SinkRefImpl.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/streamref/SinkRefImpl.scala
@@ -93,10 +93,11 @@ private[stream] final class SinkRefStageImpl[In] private[akka] (
           case OptionVal.Some(ref) ⇒
             ref ! StreamRefsProtocol.OnSubscribeHandshake(self.ref)
             tryPull()
-          case _ ⇒ // nothing to do
+          case _ ⇒
+            // only schedule timeout timer if partnerRef has not been resolved yet (i.e. if this instance of the Actor
+            // has not been provided with a valid initialPartnerRef
+            scheduleOnce(SubscriptionTimeoutTimerKey, subscriptionTimeout.timeout) // nothing to do
         }
-
-        scheduleOnce(SubscriptionTimeoutTimerKey, subscriptionTimeout.timeout)
       }
 
       lazy val initialReceive: ((ActorRef, Any)) ⇒ Unit = {
diff --git a/akka-stream/src/main/scala/akka/stream/impl/streamref/SourceRefImpl.scala b/akka-stream/src/main/scala/akka/stream/impl/streamref/SourceRefImpl.scala
index dab422f624..9f561bafdd 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/streamref/SourceRefImpl.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/streamref/SourceRefImpl.scala
@@ -89,11 +89,17 @@ private[stream] final class SourceRefStageImpl[Out](
         self = getStageActor(initialReceive)
         log.debug("[{}] Allocated receiver: {}", stageActorName, self.ref)
         if (initialPartnerRef.isDefined) // this will set the partnerRef
-          observeAndValidateSender(initialPartnerRef.get, "<no error case here, definitely valid>")
+          observeAndValidateSender(initialPartnerRef.get, "Illegal initialPartnerRef! This would be a bug in the SourceRef usage or impl.")
 
         promise.success(SinkRefImpl(self.ref))
 
-        scheduleOnce(SubscriptionTimeoutTimerKey, subscriptionTimeout.timeout)
+        partnerRef match {
+          case OptionVal.None ⇒
+            // only schedule timeout timer if partnerRef has not been resolved yet (i.e. if this instance of an Actor
+            // has not been provided with a valid initial partnerRef
+            scheduleOnce(SubscriptionTimeoutTimerKey, subscriptionTimeout.timeout) // nothing to do
+          case _ ⇒
+        }
       }
 
       override def onPull(): Unit = {
@@ -126,7 +132,7 @@ private[stream] final class SourceRefStageImpl[Out](
         case SubscriptionTimeoutTimerKey ⇒
           val ex = StreamRefSubscriptionTimeoutException(
             // we know the future has been competed by now, since it is in preStart
-            s"[$stageActorName] Remote side did not subscribe (materialize) handed out Sink reference [${promise.future.value}]," +
+            s"[$stageActorName] Remote side did not subscribe (materialize) handed out Source reference [${promise.future.value}]," +
               s"within subscription timeout: ${PrettyDuration.format(subscriptionTimeout.timeout)}!")
 
           throw ex // this will also log the exception, unlike failStage; this should fail rarely, but would be good to have it "loud"
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/StreamRefs.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/StreamRefs.scala
index d04987c28d..13a16a3a21 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/StreamRefs.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/StreamRefs.scala
@@ -5,7 +5,7 @@
 package akka.stream.scaladsl
 
 import akka.annotation.ApiMayChange
-import akka.stream.{ SinkRef, SourceRef }
+import akka.stream.{ SinkRef, SourceRef, StreamRefAttributes }
 import akka.stream.impl.streamref.{ SinkRefStageImpl, SourceRefStageImpl }
 import akka.util.OptionVal