diff --git a/src/Neo.Compiler.CSharp/CompilationEngine/CompilationContext.cs b/src/Neo.Compiler.CSharp/CompilationEngine/CompilationContext.cs
index 97af6ec15..b7e554416 100644
--- a/src/Neo.Compiler.CSharp/CompilationEngine/CompilationContext.cs
+++ b/src/Neo.Compiler.CSharp/CompilationEngine/CompilationContext.cs
@@ -159,7 +159,7 @@ internal void Compile()
                 try
                 {
 #pragma warning disable CS8600 // Converting null literal or possible null value to non-nullable type.
-                    (nef, manifest, debugInfo) = Neo.Optimizer.Optimizer.Optimize(nef, manifest, debugInfo: debugInfo!, optimizationType: Options.Optimize);
+                    (nef, manifest, debugInfo) = Neo.Optimizer.Optimizer.Optimize(nef, manifest, debugInfo: debugInfo!.Clone(), optimizationType: Options.Optimize);
 #pragma warning restore CS8600 // Converting null literal or possible null value to non-nullable type.
                 }
                 catch (Exception ex)