As bug 36549 notes, the es_indexer_daemon.pl doesn't fork child processes to do its work. This leads to memory leaks, but it also means that it's using a stale L1 cache. If you update a system preference like IncludeSeeFromInSearches, you have to restart your es_indexer_daemon.pl worker before you can re-index your database. Note that the solution to this problem does not have to be updating the daemon to fork child process workers. Rather, we need to clear the L1 cache after we fetch a job.