Every time the uploading to HockeyApp build step runs, it seems to fully upload the app but then terminate from an exception, possibly an unexpected HTTP request or response.

Uploading to HockeyApp...
<removed>.apk
Proxy Settings: For the URL https://rink.hockeyapp.net/api/2/apps/<removed>/app_versions/99.0.0]
Found proxy configuration [false]
HockeyApp Upload Speed: 82.27Mbps
org.apache.http.ConnectionClosedException: Premature end of Content-Length delimited message body (expected: 1229; received: 0
at org.apache.http.impl.io.ContentLengthInputStream.read(ContentLengthInputStream.java:178)
at org.apache.http.conn.EofSensorInputStream.read(EofSensorInputStream.java:135)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.Reader.read(Reader.java:140)
at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:2537)
at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:2516)
at org.apache.commons.io.IOUtils.copy(IOUtils.java:2493)
at org.apache.commons.io.IOUtils.copy(IOUtils.java:2441)
at org.apache.commons.io.IOUtils.toString(IOUtils.java:1084)
at hockeyapp.HockeyappRecorder.performForApplication(HockeyappRecorder.java:396)
at hockeyapp.HockeyappRecorder.perform(HockeyappRecorder.java:281)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:744)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:690)
at hudson.model.Build$BuildExecution.post2(Build.java:186)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:635)
at hudson.model.Run.execute(Run.java:1841)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:97)
at hudson.model.Executor.run(Executor.java:429)
Build step 'Upload to HockeyApp' marked build as failure 

I am uploading using an existing app ID and version provided by build parameter. I have tried this with two different API keys although authentication does not seem to be at issue. No proxy. Fails regardless of other settings in the build step.