Hi,
I would stop using .htaccess files, first, and merge all rewrite rules in the relevant vhost / Directory block. Then, I would use the rewrite log to see what is really happening.
Using multiple .htaccess files is a recipe to lose all your hair.These are Included in the directory block. My apologies for not making that more clear.
Include /etc/httpd/conf.d/domain-htaccess.htaccess
This is a site with content going back to 1996, so a lot has changed in that time, including a conversion to SEF URLs that we're currently redirecting.
I've also posted here separately about trying to figure out how to trace rewrites using LogLevel and trace, but it is very difficult to follow.
Thanks,
Dave