Hi,
You have 2 times title tag. It can seen in your pasted code as well.
<title>{$meta_title|replace:$shop_name_to_trim:''|escape:'htmlall':'UTF-8'}</title>
<meta charset="utf-8" />
<title>{$meta_title|escape:'html':'UTF-8'}</title>
Therefore double title showing on webpages. You need to keep one and remove another.
PrestaShop Tutorials Videos [How to do Tasks]
https://www.prestashop.com/forums/topic/907438-prestashop-tutorials-videos-how-to-do-tasks/