src/Pure/Thy/thy_syntax.scala

           val cmd_edits =
             removed_commands.reverse.map(cmd => (commands0.prev(cmd), None)) :::
             inserted_commands.map(cmd => (commands2.prev(cmd), Some(cmd)))
 
           doc_edits += (name -> Some(cmd_edits))
-          nodes += (name -> new Document.Node(node.header, commands2))
+          nodes += (name -> Document.Node(node.header, node.blobs, commands2))
       }
       (doc_edits.toList, new Document.Version(Document.new_id(), nodes))
     }
   }
 }