diff --git a/src/persistence/Elsa.Persistence.YesSql/Documents/WorkflowInstanceDocument.cs b/src/persistence/Elsa.Persistence.YesSql/Documents/WorkflowInstanceDocument.cs
index 56699c4b6..61815684a 100644
--- a/src/persistence/Elsa.Persistence.YesSql/Documents/WorkflowInstanceDocument.cs
+++ b/src/persistence/Elsa.Persistence.YesSql/Documents/WorkflowInstanceDocument.cs
@@ -36,8 +36,8 @@ namespace Elsa.Persistence.YesSql.Documents
         }
         
         public WorkflowFault? Fault { get; set; }
-        public Stack<ScheduledActivity> ScheduledActivities { get; set; } = new();
-        public Stack<string> Scopes { get; set; } = new();
+        public SimpleStack<ScheduledActivity> ScheduledActivities { get; set; } = new();
+        public SimpleStack<string> Scopes { get; set; } = new();
         public ScheduledActivity? CurrentActivity { get; set; }
     }
 }
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