What Happened to the Deep Research Option in My Browser?

That's odd! You might want to try typing "/" to bring up a menu. Can you still see the Deep Research option in there?

I've encountered the same issue! Double-check your settings or look for updates, as there could be compatibility problems with your browser.

It sounds like there's a restriction if you're using a custom GPT setup. Even though the Deep Research option is visible in the mobile app, it might not work properly there too, especially if you're in a specific Project.