Using safe mode to make sure there is no plugin or theme causing this
1 - correct link is requested
2 - correct content is returned
but then:
3 - fetching 404 body
logging
[db5060] Started GET "/talk/t/talk-forums-disappearing/10681?safe_mode=no_custom%2Cno_plugins%2Conly_official" for 77.163.254.28 at 2018-08-07 20:19:10 +0000
[db5060] Processing by TopicsController#show as HTML
[db5060] Parameters: {"safe_mode"=>"no_custom,no_plugins,only_official", "slug"=>"talk-forums-disappearing", "topic_id"=>"10681"}
[db5060] Rendering topics/show.html.erb within layouts/application
[db5060] Rendered topics/show.html.erb within layouts/application (6.3ms)
[db5060] Rendered layouts/_head.html.erb (0.3ms)
[db5060] Rendered common/_discourse_stylesheet.html.erb (0.1ms)
[db5060] Rendered common/_special_font_face.html.erb (0.1ms)
[db5060] Rendered application/_header.html.erb (0.2ms)
[db5060] Rendered common/_discourse_javascript.html.erb (0.3ms)
[db5060] Completed 200 OK in 124ms (Views: 9.0ms | ActiveRecord: 26.0ms)
[db5060] Started GET "/talk/404-body?_=1533673157932" for 77.163.254.28 at 2018-08-07 20:19:12 +0000
[db5060] Processing by ExceptionsController#not_found_body as HTML
[db5060] Parameters: {"_"=>"1533673157932"}
[db5060] Rendering exceptions/not_found.html.erb
[db5060] Rendered exceptions/not_found.html.erb (15.3ms)
[db5060] Rendering html template
[db5060] Rendered html template (0.0ms)
[db5060] Completed 200 OK in 52ms (Views: 0.3ms | ActiveRecord: 11.6ms)