When secure .htaccess is locked all permalinks return a 404 error

Hi, since upgrading to 50.1 I have had an issue with my permalinks. I believe it is a conflict between the WMPL plugins and the BPS security plugin.

I have WPML installed, I have around 8 different languages with English as the default. My permalink settings are: /%year%/%monthnum%/%postname%/. My Woocommerce product permalink base is: product.

WPML Language URL format:

Different languages in directories: https://mysite.net/international/ – English, https://mysite.net/international/nl/ – Dutch

Now when I implement secure htaccess through BPS security all urls apart from home (default language) return a 404 error. As soon as I unlock the .htaccess and resave the permalinks everything returns to normal. But obviously I am no longer protected by BPS security.

Do I have to add WPML as an exception or something to the secure .htaccess page? Or is there something else that I need to do to make these two play nicely together?

Any help would be much appreciated. Many thanks, Olly

https://www.ads-software.com/plugins/bulletproof-security/