Exclude subfolder from WP-redirect works with html however not php recordsdata

I desire a sure subfolder excluded from being dealt with by WP with its 404 – web page not discovered message.

My drawback is:

• instance.com/Non_WP/myfile.html – reveals appropriately

however

• instance.com/Non_WP/myfile.php – will set off a WP 404-page not discovered message.

Each recordsdata, myfile.html and myfile.php exist within the Non_WP folder.

My .htaccess file appears to be like like this:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} !^/(Non_WP|Non_WP/.*)$ 
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

It ought to exclude WP from dealing with the “Non_WP” folder.

WP is put in within the root folder and there aren’t any redirect-plugins energetic.

Any thought what I am doing incorrect? Any thought the place to find the issue apart from the .htaccess file?