Hi,
For your original issue , please check my screenshot
View post on imgur.com
cache-control: public, max-age=7776000
this header will instruct browser to cache the page for 7776000 seconds , which even you changed in your WP, if user doesn’t force refresh it , browser won’t load new content until 90 days later.
you should NEVER EVER set this header on dynamic page unless your site is mostly-static and never change contents.
for your second issue, you have sort of mess’ed up .htaccess content , you need to try to clean it up ,remove un-need or unused content out of it.
Best regards,