I have the same problem. It’s not redirecting from https to http. I have this:
RewriteEngine On
<IfModule mod_rewrite.c>
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress
# force all URLs from https to http
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^blog\. [NC]
RewriteCond %{HTTPS} off
RewriteRule ^ https://blog.%{HTTP_HOST}%{REQUEST_URI} [R=301,L,NE]
</IfModule>
