Object reference not set error - StreamBlockSplitter

I recently got this error on a machine running 2.0.4.38. I searched the forum and didn’t see any other posts about NullReferenceException combined with StreamBlockSplitter so I thought I should start a new topic.

Failed: Object reference not set to an instance of an object.
Details: System.NullReferenceException: Object reference not set to an instance of an object.
   at Duplicati.Library.Main.Operation.Backup.StreamBlockSplitter.<>c__DisplayClass2_0.<<Run>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at CoCoL.AutomationExtensions.<RunTask>d__10`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Duplicati.Library.Main.Operation.BackupHandler.<RunMainOperation>d__13.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Duplicati.Library.Main.Operation.BackupHandler.<RunAsync>d__20.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at CoCoL.ChannelExtensions.WaitForTaskOrThrow(Task task)
   at Duplicati.Library.Main.Controller.<>c__DisplayClass14_0.<Backup>b__0(BackupResults result)
   at Duplicati.Library.Main.Controller.RunAction[T](T result, String[]& paths, IFilter& filter, Action`1 method)

Log data:
2020-01-03 12:00:19 -08 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
System.NullReferenceException: Object reference not set to an instance of an object.
   at Duplicati.Library.Main.Operation.Backup.StreamBlockSplitter.<>c__DisplayClass2_0.<<Run>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at CoCoL.AutomationExtensions.<RunTask>d__10`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Duplicati.Library.Main.Operation.BackupHandler.<RunMainOperation>d__13.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Duplicati.Library.Main.Operation.BackupHandler.<RunAsync>d__20.MoveNext()

I re-ran the backup job and it worked fine. Not sure what caused it. I don’t think I’ve ever seen this one before in my 2+ years of Duplicati use.