> Lots of issues like this due to an overly dynamic site.
Rarely are UX issues there because of anything technical at all, just poor testing and poor polishing. Of course, things are way easier with a static site, since the back button Just Works(TM) in that case, but doesn't mean "overly dynamic sites" cannot have proper browser history.
The "trendy stack" comment seems misplaced. CS is famously written in Ruby on Rails, not PHP, perhaps one of the most "trendy" stacks at the time[0]. Coincidentally, CS is also awfully slow with frequent errors. Managing all my guests when my city was in high season was usually much easier to do via WhatsApp.
To be honest, as a top host in my city, the only features that Couchsurfing was actually good for was discovery. Everything else was kinda broken or slow. It added to the charm, but it definitely wasn't much better than what you're claiming here for Couchers.