Accumulators are not UI accessible running in FLIP-6 mode

Using 1.5-rc2, when I run a job in flip-6 mode and try to access Accumulators in the UI nothing shows. Looking at the Job manager log there is this error: 
 
2018-05-11 17:09:04,707 ERROR org.apache.flink.runtime.rest.handler.job.SubtaskCurrentAttemptDetailsHandler - Could not create the handler request.
org.apache.flink.runtime.rest.handler.HandlerRequestException: Cannot resolve path parameter (subtaskindex) from value "accumulators".
at org.apache.flink.runtime.rest.handler.HandlerRequest.<init>(HandlerRequest.java:61)
at org.apache.flink.runtime.rest.AbstractHandler.respondAsLeader(AbstractHandler.java:155)
at org.apache.flink.runtime.rest.handler.RedirectHandler.lambda$null$0(RedirectHandler.java:139)
at java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:760)
at java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:736)
at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:442)
at org.apache.flink.shaded.netty4.io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:357)
at org.apache.flink.shaded.netty4.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357)
at org.apache.flink.shaded.netty4.io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:111)
at org.apache.flink.shaded.netty4.io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137)
at java.lang.Thread.run(Thread.java:748)
 
This error does not occur when running the same job in legacy mode.