What potential issues can arise with PHP cookies not being saved in certain browsers like Opera and IE?

Potential issues that can arise with PHP cookies not being saved in certain browsers like Opera and IE include compatibility issues with how these browsers handle cookie settings. To solve this issue, you can explicitly set the cookie path and domain to ensure that the cookies are saved and accessible across different browsers.

setcookie('cookie_name', 'cookie_value', time() + 3600, '/', 'yourdomain.com');