htaccess sporadically blocking site monitor

We use a site monitor "UR", and I whitelisted their IP addresses in our WHM. On one of the sites we host, about half of times the UR bot checks in, it results in a 403 error. I double-checked my whitelist/blacklist, then decided in must be the htaccess. Below are typical recent error msg followed by sanitized htaccess. Bold IP is legit for the UR bot. [Tue Dec 04 11:55:30.801144 2018] [access_compat:error] [pid 9603:tid 47443861387008] [client 63.143.xx.xxx:34758] AH01797: client denied by server configuration: /home/admin/public_html/exampledomain.com/wp-content/cache/all/index.html, referer: + [NC] RewriteCond %{HTTP_USER_AGENT} !^.*(\bCrMo\b|CriOS|Android.*Chrome\/[.0-9]*\s(Mobile)?|\bDolfin\b|Opera.*Mini|Opera.*Mobi|Android.*Opera|Mobile.*OPR\/[0-9.]+|Coast\/[0-9.]+|Skyfire|Mobile\sSafari\/[.0-9]*\sEdge|IEMobile|MSIEMobile|fennec|firefox.*maemo|(Mobile|Tablet).*Firefox|Firefox.*Mobile|FxiOS|bolt|teashark|Blazer|Version.*Mobile.*Safari|Safari.*Mobile|MobileSafari|Tizen|UC.*Browser|UCWEB|baiduboxapp|baidubrowser|DiigoBrowser|Puffin|\bMercury\b|Obigo|NF-Browser|NokiaBrowser|OviBrowser|OneBrowser|TwonkyBeamBrowser|SEMC.*Browser|FlyFlow|Minimo|NetFront|Novarra-Vision|MQQBrowser|MicroMessenger|Android.*PaleMoon|Mobile.*PaleMoon|Android|blackberry|\bBB10\b|rim\stablet\sos|PalmOS|avantgo|blazer|elaine|hiptop|palm|plucker|xiino|Symbian|SymbOS|Series60|Series40|SYB-[0-9]+|\bS60\b|Windows\sCE.*(PPC|Smartphone|Mobile|[0-9]{3}x[0-9]{3})|Window\sMobile|Windows\sPhone\s[0-9.]+|WCE;|Windows\sPhone\s10.0|Windows\sPhone\s8.1|Windows\sPhone\s8.0|Windows\sPhone\sOS|XBLWP7|ZuneWP7|Windows\sNT\s6\.[23]\;\sARM\;|\biPhone.*Mobile|\biPod|\biPad|Apple-iPhone7C2|MeeGo|Maemo|J2ME\/|\bMIDP\b|\bCLDC\b|webOS|hpwOS|\bBada\b|BREW).*$ [NC] RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/all/$1/index.html -f [or] RewriteCond /home/admin/public_html/exampledomain.com/wp-content/cache/all/$1/index.html -f RewriteRule ^(.*) "/wp-content/cache/all/$1/index.html" [L] AddDefaultCharset UTF-8 FileETag None Header unset ETag Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate" Header set Pragma "no-cache" Header set Expires "Mon, 29 Oct 1923 20:30:00 GMT" # END WpFastestCache # BEGIN GzipWpFastestCache AddType x-font/woff .woff AddType x-font/ttf .ttf AddOutputFilterByType DEFLATE image/svg+xml AddOutputFilterByType DEFLATE text/plain AddOutputFilterByType DEFLATE text/html AddOutputFilterByType DEFLATE text/xml AddOutputFilterByType DEFLATE text/css AddOutputFilterByType DEFLATE text/javascript AddOutputFilterByType DEFLATE application/xml AddOutputFilterByType DEFLATE application/xhtml+xml AddOutputFilterByType DEFLATE application/rss+xml AddOutputFilterByType DEFLATE application/javascript AddOutputFilterByType DEFLATE application/x-javascript AddOutputFilterByType DEFLATE application/x-font-ttf AddOutputFilterByType DEFLATE application/vnd.ms-fontobject AddOutputFilterByType DEFLATE font/opentype font/ttf font/eot font/otf # END GzipWpFastestCache # BEGIN LBCWpFastestCache AddType application/font-woff2 .woff2 ExpiresActive On ExpiresDefault A0 ExpiresByType video/webm A2592000 ExpiresByType video/ogg A2592000 ExpiresByType video/mp4 A2592000 ExpiresByType image/webp A2592000 ExpiresByType image/gif A2592000 ExpiresByType image/png A2592000 ExpiresByType image/jpg A2592000 ExpiresByType image/jpeg A2592000 ExpiresByType image/ico A2592000 ExpiresByType image/svg+xml A2592000 ExpiresByType text/css A2592000 ExpiresByType text/javascript A2592000 ExpiresByType application/javascript A2592000 ExpiresByType application/x-javascript A2592000 ExpiresByType application/font-woff2 A2592000 Header set Expires "max-age=2592000, public" Header unset ETag Header set Connection keep-alive FileETag None # END LBCWpFastestCache # BEGIN WordPress RewriteEngine On RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L] # END WordPress # directory browsing Options All -Indexes # Block include-only files RewriteEngine On RewriteBase / RewriteRule ^wp-admin/includes/ - [F,L] RewriteRule !^wp-includes/ - [S=3] RewriteRule ^wp-includes/[^/]+\.php$ - [F,L] RewriteRule ^wp-includes/js/tinymce/langs/.+\.php - [F,L] RewriteRule ^wp-includes/theme-compat/ - [F,L] # protect config file order allow,deny deny from all # protect htaccess itself Require all denied # Files types which probably don't ever need to be accessed on production machines Require all denied Order allow,deny deny from all # php -- BEGIN cPanel-generated handler, do not edit # NOTE this account's php is controlled via FPM and the vhost, this is a place holder. # Do not edit. This next line is to support the cPanel php wrapper (php_cli). # AddType application/x-httpd-ea-php72 .php .phtml # php -- END cPanel-generated handler, do not edit