ThresholdLoggingTracer throws System.ArgumentNullException during processing

2018-09-28 01:54:10,606 [6] ERROR Couchbase.Tracing.ThresholdLoggingTracer - Error when procesing spans for spans over serivce thresholds

System.ArgumentNullException: Value cannot be null.

   at System.Threading.SemaphoreSlim.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)

   at System.Collections.Concurrent.BlockingCollection`1.TryTakeWithNoTimeValidation(T& item, Int32 millisecondsTimeout, CancellationToken cancellationToken, CancellationTokenSource combinedTokenSource)

   at System.Collections.Concurrent.BlockingCollection`1.TryTake(T& item, Int32 millisecondsTimeout, CancellationToken cancellationToken)

   at Couchbase.Tracing.ThresholdLoggingTracer.<DoWork>d__57.MoveNext()