Optimised titles not showing in browser tabs

Hi, the optimised titles for this site (pages and posts) are not showing on the browser tabs (currently defaulting to the hyperlink) despite the fact that [ rewrite titles ] is enabled, page title format is [ %page_title% ] and post title format is [ %post_title% ]. Not sure what we’re missing.

Many thanks,

Raquel

The page I need help with: [log in to see the link]