diff --git a/src/coreclr/System.Private.CoreLib/src/System/StubHelpers.cs b/src/coreclr/System.Private.CoreLib/src/System/StubHelpers.cs
index 6d9c3d7680f31..3c9c08b7c0e81 100644
--- a/src/coreclr/System.Private.CoreLib/src/System/StubHelpers.cs
+++ b/src/coreclr/System.Private.CoreLib/src/System/StubHelpers.cs
@@ -802,17 +802,19 @@ internal static unsafe void ConvertContentsToNative(ICustomMarshaler marshaler,
             // COMPAT: We never pass null to MarshalManagedToNative.
             if (pManagedHome is null)
             {
+                *pNativeHome = IntPtr.Zero;
                 return;
             }
 
             *pNativeHome = marshaler.MarshalManagedToNative(pManagedHome);
         }
 
-        internal static void ConvertContentsToManaged(ICustomMarshaler marshaler, ref object pManagedHome, IntPtr* pNativeHome)
+        internal static void ConvertContentsToManaged(ICustomMarshaler marshaler, ref object? pManagedHome, IntPtr* pNativeHome)
         {
             // COMPAT: We never pass null to MarshalNativeToManaged.
             if (*pNativeHome == IntPtr.Zero)
             {
+                pManagedHome = null;
                 return;
             }