You are never setting [@metadata][id], so this will result in every document having the same _id. You are fetching data from 27 tables and writing every document from every table to 27 indexes with the same _id.
It is hard to believe that you really want to do that. If you want to copy each table to a separate index then use conditionals (this thread and this thread might help), or, probably better, use pipelines.conf to configure 27 pipelines to do it.