Hi,
Thank you for your support and my apology for this late response cause I was on the road.
Yes I use only a Notepad++ for editing but in this case I just copy/pasted from right to left text box (UI: BulletProof Security ~ htaccess Core > Custom Code), so no other text editor was involved.
I figured that the lines of code from current root .htaccess file in htaccess File Editor (UI: BulletProof Security ~ htaccess Core > File Editor), was different then the same lines in similar htaccess files on other 3 sites [another server].
Using UI: BulletProof Security ~ htaccess Core > Custom Code somehow one line was deleted at creation of new htaccess file, this is how it looks:
# WP REWRITE LOOP START
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
# CUSTOM CODE REQUEST METHODS FILTERED
# REQUEST METHODS FILTERED
# If you want to allow HEAD Requests use BPS Custom Code and copy
# this entire REQUEST METHODS FILTERED section of code to this BPS Custom Code
# text box: CUSTOM CODE REQUEST METHODS FILTERED.
# See the CUSTOM CODE REQUEST METHODS FILTERED help text for additional steps.
RewriteCond %{REQUEST_METHOD} ^(TRACE|DELETE|TRACK|DEBUG) [NC]
RewriteRule ^(.*)$ - [F]
RewriteCond %{REQUEST_METHOD} ^(HEAD) [NC]
RewriteRule ^(.*)$ /wp-content/plugins/bulletproof-security/405.php [L]
So I just added a line between:
RewriteRule ^index\.php$ - [L]
and
# CUSTOM CODE REQUEST METHODS FILTERED
and all problems was gone!