diff --git a/src/System.Management.Automation/engine/remoting/client/Job.cs b/src/System.Management.Automation/engine/remoting/client/Job.cs
index b88e8003945..48c2fd4e34a 100644
--- a/src/System.Management.Automation/engine/remoting/client/Job.cs
+++ b/src/System.Management.Automation/engine/remoting/client/Job.cs
@@ -4518,9 +4518,10 @@ internal OutputProcessingStateEventArgs(bool processingOutput)
         }
     }
 
+#nullable enable
     internal interface IOutputProcessingState
     {
-        event EventHandler<OutputProcessingStateEventArgs> OutputProcessingStateChanged;
+        event EventHandler<OutputProcessingStateEventArgs>? OutputProcessingStateChanged;
     }
 
     #endregion