Hello, @arvinbai,
1. Could you please share the page URL of the product having that issue, so that I can have a look into it for you on your site.
2. Please navigate to Porto >> Template Builder >> Header, edit the header with page builder, and then set the mobile header from there as per your requirements: Please refer to this screenshot: https://pasteboard.co/H43O216X6VNe.png
Best Regards,
PThemes Team.