Postgres text search has unexpected query conversion
You have created a new dictionary and such, but you are not using it.

SELECT to_tsquery('simple_english_with_stopwords','off &lt;-&gt; plan');
    to_tsquery    
------------------
 'off' &lt;-&gt; 'plan'
(1 row)


Or:

set default_text_search_config TO 'simple_english_with_stopwords';
SELECT to_tsquery('off &lt;-&gt; plan');
    to_tsquery    
------------------
 'off' &lt;-&gt; 'plan'


The first, more verbose, option is better if you want to use FTS indexes, otherwise you run into mutability problems.