Resolution:
When using the .NET Driver, you may see occasional .NET Driver logs that are similar to this

Warning: [ClusterServiceManager] Error: no handler found for service 3627909640516263762-2435895751334858626, invocation 23

This indicates that the Driver timed out while submitting a task, but the task has already been submitted on the Broker, so a duplicate task is submitted. This is usually due to heavy load on the Broker. It's usually a minor problem, since the only effect is creating an extra task. If it repeatedly happens, increase the HTTP timeout on the Driver.