Magento – Success message won’t disappear in the home page Magento 2

For me this issue was being caused by the message block not being present on the page. Try loading other pages that you have modified less.

Take a look: vendor/magento/module-review/Controller/Product/Post.php

public function execute()
 {
   ......
   $this->messageManager->addSuccess(__('You submitted your review for moderation.'));
   ......
 }

When we want to set this message, we have two options:
+We can use translation.
+We can override this class.

Note: the global message may store in local storage