Photo upload feedback is failing?

(Bug, Closed -> Fixed, Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Summary: Kate has also reported this. I don't know if it's consistent, but I've observed the upload process getting going, and then appearing to hang in the UI.
The upload itself is entirely successful, but the UI never completes, and internally we're getting this Exception:
! @6od8e2chc - Internal server error, for (POST) [/u/jducoeur/.3y284n2/_photoUpload?thingId=.3y28aby&propId=3y28abx] ->

play.api.Application$$anon$1: Execution exception[[AskTimeoutException: Ask timed out on [Actor[akka://application/user/sharding/Space/3y284n2/$a#-25715190]] after [30000 ms]]]
        at play.api.Application$class.handleError(Application.scala:296) ~[com.typesafe.play.play_2.11-2.3.10.jar:2.3.10]
        at play.api.DefaultApplication.handleError(Application.scala:402) [com.typesafe.play.play_2.11-2.3.10.jar:2.3.10]
        at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320) [com.typesafe.play.play_2.11-2.3.10.jar:2.3.10]
        at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320) [com.typesafe.play.play_2.11-2.3.10.jar:2.3.10]
        at scala.Option.map(Option.scala:146) [org.scala-lang.scala-library-2.11.7.jar:na]
        at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3.applyOrElse(PlayDefaultUpstreamHandler.scala:320) [com.typesafe.play.play_2.11-2.3.10.jar:2.3.10]
        at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3.applyOrElse(PlayDefaultUpstreamHandler.scala:316) [com.typesafe.play.play_2.11-2.3.10.jar:2.3.10]
        at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:344) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:343) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32) [org.scala-lang.scala-library-2.11.7.jar:na]
        at play.api.libs.iteratee.Execution$trampoline$.execute(Execution.scala:46) [com.typesafe.play.play-iteratees_2.11-2.3.10.jar:2.3.10]
        at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:40) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:248) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.Promise$class.complete(Promise.scala:55) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.impl.Promise$DefaultPromise.complete(Promise.scala:153) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.Future$$anonfun$flatMap$1.apply(Future.scala:249) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.Future$$anonfun$flatMap$1.apply(Future.scala:249) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.forkjoin.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1361) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [org.scala-lang.scala-library-2.11.7.jar:na]
Caused by: akka.pattern.AskTimeoutException: Ask timed out on [Actor[akka://application/user/sharding/Space/3y284n2/$a#-25715190]] after [30000 ms]
        at akka.pattern.PromiseActorRef$$anonfun$1.apply$mcV$sp(AskSupport.scala:334) ~[com.typesafe.akka.akka-actor_2.11-2.3.11.jar:na]
        at akka.actor.Scheduler$$anon$7.run(Scheduler.scala:117) ~[com.typesafe.akka.akka-actor_2.11-2.3.11.jar:na]
        at scala.concurrent.Future$InternalCallbackExecutor$.unbatchedExecute(Future.scala:599) ~[org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.BatchingExecutor$class.execute(BatchingExecutor.scala:109) ~[org.scala-lang.scala-library-2.11.7.jar:na]
        at scala.concurrent.Future$InternalCallbackExecutor$.execute(Future.scala:597) ~[org.scala-lang.scala-library-2.11.7.jar:na]
        at akka.actor.LightArrayRevolverScheduler$TaskHolder.executeTask(Scheduler.scala:467) ~[com.typesafe.akka.akka-actor_2.11-2.3.11.jar:na]
        at akka.actor.LightArrayRevolverScheduler$$anon$8.executeBucket$1(Scheduler.scala:419) ~[com.typesafe.akka.akka-actor_2.11-2.3.11.jar:na]
        at akka.actor.LightArrayRevolverScheduler$$anon$8.nextTick(Scheduler.scala:423) ~[com.typesafe.akka.akka-actor_2.11-2.3.11.jar:na]
        at akka.actor.LightArrayRevolverScheduler$$anon$8.run(Scheduler.scala:375) ~[com.typesafe.akka.akka-actor_2.11-2.3.11.jar:na]
        at java.lang.Thread.run(Thread.java:662) ~[na:1.6.0_38]
30 seconds is a pretty long time, so I suspect the problem isn't just slowness, that something's actually wrong.
Whatever the problem is, it's intermittent -- when I try to repro the problem in the Beta Sandbox, it's not happening...