redirect in custom post search

Hi, I find that what it was working previously in a wordpress site I created, it is now not working anymore.
I create a custom post type and an advanced filtering/search for it but it is now not working anymore.
In particular it is not workling in the main language (english) but it works in the other languages. Also in other languages it wont' paginate.

It is a strange behaviour and I cannot figure out why it happen, because I didn't change any line of code.

I think it is related to the rewrite rule, but I'm confused. Can you help me?

Here the rewrite rule:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
# se non c'è pagina la metto io
RewriteCond %{QUERY_STRING} ^(\bslcCat\b=(.*))$
RewriteRule ^search/(.*)$ [R=QSA,L]
#aggiorno il valore della pagina sulla base del parametro stringa
RewriteCond %{QUERY_STRING} ^page=(.*)&(.*)&(.*)&(.*)&(.*)?$
RewriteRule ^search/page/([0-9]+)/$$1&%2&%3&%4&%5 [L]
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]


Here the search (try the advance filtering on the right):

Thank you