The RPC server is unavailable - exception seen during Jenkins pipeline execution of HP LR plugin

We're trying to invoke a LR scenario from Jenkins via pipeline code using the loadRunnerTest step, but when the test completes there is an error right after the 'closing controller' step. The error says 'RPC server is unavailable'.. logs copied below for the relevant section.

there are no remote load generators used here. And we're on LR 12.5. Anyone else seen this before? 

Analyzing results...
closing Controller

Unhandled Exception: System.Runtime.InteropServices.COMException: The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
   at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
   at HP.LoadRunner.Interop.Wlrun.LrEngineClass.get_Scenario()
   at HpToolsLauncher.TestRunners.PerformanceTestRunner.updateVuserStatus()
   at HpToolsLauncher.TestRunners.PerformanceTestRunner.isFinished()
   at HpToolsLauncher.TestRunners.PerformanceTestRunner.DoTask(Object state)
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()
Recording test results
None of the test reports contained any result
RunResultRecorder: didn't find any test results to record