diff --git a/Stack/Opc.Ua.Core/Stack/State/NodeState.cs b/Stack/Opc.Ua.Core/Stack/State/NodeState.cs
index ef96146731..f92b26afc2 100644
--- a/Stack/Opc.Ua.Core/Stack/State/NodeState.cs
+++ b/Stack/Opc.Ua.Core/Stack/State/NodeState.cs
@@ -3667,7 +3667,7 @@ namespace Opc.Ua
                         result = onReadAccessRestrictions(context, this, ref accessRestrictions);
                     }
 
-                    if (ServiceResult.IsGood(result))
+                    if (ServiceResult.IsGood(result) && accessRestrictions != null)
                     {
                         value = (ushort)accessRestrictions;
                     }