CodeIgniter is putting the base URL in front of external site link

I am using Codeigniter on the backend. I have removed the controller names visibility in the URL by using the below Routes configuration:

$route['default_controller'] = 'home';
$route['(:any)'] = 'CommonPages/postDetails/$1';
$route['(:num)'] = 'CommonPages/postDetails/$1';
$route['([a-zA-Z0-9]+)'] = 'CommonPages/postDetails/$1';
$route['404_override'] = '';
$route['translate_uri_dashes'] = FALSE;

The above sample code gives the exact result I want eg: base url + post title.
eg: https://example.com/how-to-install-whatsapp

Now I am having issues with the external sites links that is embedded under my blog posts. When I click on the external site link, it is putting my website base url infront of it + the external site url in double courts”” and that makes it not functional. eg:

 <a href=”https://play.google.com/store/apps/details?id=com.dewmobile.kuaiya.play&hl=en&gl=US” target=”_blank”>Play Store  (Zapya)</a> </b>

It is giving me the below result which is not functional:

https://example.com/"https://play.google.com/store/apps/details?id=com.dewmobile.kuaiya.play&hl=en&gl=US"

here is a screenshot below:

Any help will be much appreciated 🙂

Thanks.