diff --git a/margin-notes/margin-notes.lua b/margin-notes/margin-notes.lua
index c7b639e..a880218 100644
--- a/margin-notes/margin-notes.lua
+++ b/margin-notes/margin-notes.lua
@@ -419,23 +419,35 @@ end
 
 local function template_to_function(template)
   --[[
-    inlines_with_placeholders cannot be memoized
-    for it is a reference to a table that will be changed
-    by replace_placeholders.
-    paths_to_placeholders can be memoized
-    because it is only traversed once it has been created.
+    Returns a function that takes data and inserts it
+    into the given template.
+  ]]--
+  --[[
+    – inlines_with_placeholders and paths_to_placeholders
+      are created and memoized the first time the returned
+      function is called.
+    – inlines_with_placeholders cannot be used directly
+      for it is a reference to a table that would be changed
+      by replace_placeholders. That's why we create a deep
+      copy of it via the walk function at every call.
+    – paths_to_placeholders can be used directly by
+      replace_placeholders because it is only traversed.
   ]]--
   if template then
     local paths_to_placeholders
+    local inlines_with_placeholders
     return
       function(instance_content, instance_attr)
-        local inlines_with_placeholders = template_to_pandoc_fragment(template)
+        if not inlines_with_placeholders then
+          inlines_with_placeholders = template_to_pandoc_fragment(template)
+        end
+        local inlines_copy = inlines_with_placeholders:walk({})
         if not paths_to_placeholders then
           paths_to_placeholders =
             get_paths_to_placeholders(inlines_with_placeholders)
         end
         return replace_placeholders(
-          inlines_with_placeholders, paths_to_placeholders,
+          inlines_copy, paths_to_placeholders,
           instance_content, instance_attr)
       end
   end