htaccess breaks permalinks

Very strange situation that we have experienced today. The .htaccess has just randomly stopped the pretty permalinks from working.

This is the structure of my .htaccess:

# snip
#Begin Really Simple Security
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteCond %{REQUEST_URI} !^/\.well-known/acme-challenge/
RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R=301,L]
</IfModule>

Options -Indexes
#End Really Simple Security

# BEGIN WordPress
# The directives (lines) between "BEGIN WordPress" and "END WordPress" are
# dynamically generated, and should only be modified via WordPress filters.
# Any changes to the directives between these markers will be overwritten.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress
# snip

And any page under the root, with a pretty permalink, has stopped working.

I moved the WordPress block up to the top and it works, so I moved it down block by block until I found it was the Really Simple SSL block.

Specifically the RewriteRule line (I tried selectively commenting out each of the RewriteCond).

If I move the WordPress block up above the Really Simple Security block then it all goes back to normal.

I dont know if the cache has masked this, or what could have happened, as your last release was 3 weeks ago, and other staff have been working on the pages and only just found this issue.

Really not sure what could have happened but thought I would document it in as much detail as I could in case it is the start of an issue for others.

The site is hosted on litespeed server. Hosting company is guru.co.uk.

Really-Simple-Plugins / really-simple-ssl

htaccess breaks permalinks #604