Braden I noticed that as well. That's related to the "in-app back button" feature which is completely undocumented and I'm not sure any developer active on Flarum nowadays know how it was originally supposed to work 😅
Basically for the "back" button to work, a page must register itself into a page history recorder component. But very few pages actually register themselves, I think it might be just the home page. Which can lead to confusing behavior because the back button sometimes takes you a few pages back since the intermediate pages might not have registered themselves.
If you start navigation from a discussion and never to go the homepage, I think you might not see the back button at all, because there's no page registered in the history component at this point.
We should probably standardize this properly in the future and require either all pages and extensions to use the feature, or drop it entirely.
The problem of using it for every page, is that the hamburger menu will then become inaccessible since it only shows up when there's no back button on mobile. So that part would require a redesign as well.
