meta_query with more than 9 arrays?

Hello

I’ve got very strange problem using meta_query. It works fine until you select more than 9 checkboxes on the search.
My code is like this for each field:
if ($_POST[‘gym’] == ‘1’) {
$metas[] = array(
‘key’ => ‘qit_gym’,
‘value’ => serialize(strval($_POST[‘gym’])),
‘compare’ => ‘LIKE’
);
}

Where $metas[] is my array for all checkboxes. Then create the query with the other variables:
$totalquery = array(
‘types’ => $s_type,
‘locations’ => $s_location,
‘post_type’ => ‘estates’,
‘posts_per_page’ => $per_page,
‘meta_query’ => $metas
);
$search_query = new WP_Query($totalquery);

Tested on WP 3.2 and 3.3 -> not working.

Does anybody knows if there is particular limitation or it is a bug?