Periodic exception: java.util.NoSuchElementException: backend-response-forwarder

[andrewhall-premier]

Periodically receiving the following Exception when the mavenproxy is attempting cleanup. I can't narrow down the scenario; consequently, I can't provide a test case. However, I suggest first checking for the presence of the channel handler. FYI - the exception does not appear to actually break anything and the task completes successfully

[-----:~/code/kotlin-prototype] master(+24/-104)+ ± ./gradlew buildApplicationDockerImage
Failed to mark a promise as failure because it has succeeded already: DefaultChannelPromise@75b671cf(success)
java.util.NoSuchElementException: backend-response-forwarder
        at io.netty.channel.DefaultChannelPipeline.getContextOrDie(DefaultChannelPipeline.java:1073)
        at io.netty.channel.DefaultChannelPipeline.remove(DefaultChannelPipeline.java:423)
        at org.unbrokendome.awscodeartifact.mavenproxy.ProxyFrontendHandler.cleanupBackendChannel(ProxyFrontendHandler.kt:393)
        at org.unbrokendome.awscodeartifact.mavenproxy.ProxyFrontendHandler.cleanupAllState(ProxyFrontendHandler.kt:378)
        at org.unbrokendome.awscodeartifact.mavenproxy.ProxyFrontendHandler.afterResponseSent(ProxyFrontendHandler.kt:362)
        at org.unbrokendome.awscodeartifact.mavenproxy.ProxyFrontendHandler.write(ProxyFrontendHandler.kt:271)
        at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717)
        at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:709)
        at io.netty.channel.AbstractChannelHandlerContext$WriteTask.run(AbstractChannelHandlerContext.java:1069)
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:834)
<======-------> 50% CONFIGURING [6s]
> :migrations > Resolve files of :migrations:classpath