Não tenho certeza se devo postar na categoria de plugin de chat em vez daqui.
De qualquer forma, instalar o plugin oficial leva a erros 500 ao tentar refazer posts.
Veja: Migrate a phpBB3 forum to Discourse - #678 by Canapin
Mesmo em modo de segurança com o plugin desativado.
Instalei o plugin de chat em outra instância e ele também acionou o problema, então tenho 100% de certeza de que o problema vem do plugin.
Após instalá-lo em meu outro fórum para testar:
Algo em /logs?
Sim, com certeza. Eu deveria ter postado aqui em vez de confiar no outro tópico.
Os logs de erro realmente mencionam o plugin de chat.
O discourse-chat é mencionado na primeira linha de ambas as abas “backtraces”:
ArgumentError (número incorreto de argumentos (dado 0, esperado 1)) lib/guardian/ensure_magic.rb:11:in 'method_missing' app/controllers/posts_controller.rb:570:in 'rebake' app/controllers/application_cont
plugins/discourse-chat/lib/guardian_extensions.rb:71:in `can_rebake?'
lib/guardian/ensure_magic.rb:11:in `method_missing'
app/controllers/posts_controller.rb:570:in `rebake'
actionpack (6.1.4.1) lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack (6.1.4.1) lib/abstract_controller/base.rb:228:in `process_action'
actionpack (6.1.4.1) lib/action_controller/metal/rendering.rb:30:in `process_action'
actionpack (6.1.4.1) lib/abstract_controller/callbacks.rb:42:in `block in process_action'
activesupport (6.1.4.1) lib/active_support/callbacks.rb:117:in `block in run_callbacks'
app/controllers/application_controller.rb:397:in `block in with_resolved_locale'
i18n (1.10.0) lib/i18n.rb:328:in `with_locale'
app/controllers/application_controller.rb:397:in `with_resolved_locale'
activesupport (6.1.4.1) lib/active_support/callbacks.rb:126:in `block in run_callbacks'
activesupport (6.1.4.1) lib/active_support/callbacks.rb:137:in `run_callbacks'
actionpack (6.1.4.1) lib/abstract_controller/callbacks.rb:41:in `process_action'
actionpack (6.1.4.1) lib/action_controller/metal/rescue.rb:22:in `process_action'
actionpack (6.1.4.1) lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
activesupport (6.1.4.1) lib/active_support/notifications.rb:203:in `block in instrument'
activesupport (6.1.4.1) lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport (6.1.4.1) lib/active_support/notifications.rb:203:in `instrument'
actionpack (6.1.4.1) lib/action_controller/metal/instrumentation.rb:33:in `process_action'
actionpack (6.1.4.1) lib/action_controller/metal/params_wrapper.rb:249:in `process_action'
activerecord (6.1.4.1) lib/active_record/railties/controller_runtime.rb:27:in `process_action'
actionpack (6.1.4.1) lib/abstract_controller/base.rb:165:in `process'
actionview (6.1.4.1) lib/action_view/rendering.rb:39:in `process'
rack-mini-profiler (3.0.0) lib/mini_profiler/profiling_methods.rb:85:in `block in profile_method'
actionpack (6.1.4.1) lib/action_controller/metal.rb:190:in `dispatch'
actionpack (6.1.4.1) lib/action_controller/metal.rb:254:in `dispatch'
actionpack (6.1.4.1) lib/action_dispatch/routing/route_set.rb:50:in `dispatch'
actionpack (6.1.4.1) lib/action_dispatch/routing/route_set.rb:33:in `serve'
actionpack (6.1.4.1) lib/action_dispatch/journey/router.rb:50:in `block in serve'
actionpack (6.1.4.1) lib/action_dispatch/journey/router.rb:32:in `each'
actionpack (6.1.4.1) lib/action_dispatch/journey/router.rb:32:in `serve'
actionpack (6.1.4.1) lib/action_dispatch/routing/route_set.rb:842:in `call'
lib/middleware/omniauth_bypass_middleware.rb:71:in `call'
rack (2.2.3) lib/rack/tempfile_reaper.rb:15:in `call'
rack (2.2.3) lib/rack/conditional_get.rb:40:in `call'
rack (2.2.3) lib/rack/head.rb:12:in `call'
actionpack (6.1.4.1) lib/action_dispatch/http/permissions_policy.rb:22:in `call'
lib/content_security_policy/middleware.rb:12:in `call'
lib/middleware/anonymous_cache.rb:358:in `call'
rack (2.2.3) lib/rack/session/abstract/id.rb:266:in `context'
rack (2.2.3) lib/rack/session/abstract/id.rb:260:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/cookies.rb:689:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
activesupport (6.1.4.1) lib/active_support/callbacks.rb:98:in `run_callbacks'
actionpack (6.1.4.1) lib/action_dispatch/middleware/callbacks.rb:26:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/actionable_exceptions.rb:18:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/debug_exceptions.rb:29:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
logster (2.10.1) lib/logster/middleware/reporter.rb:43:in `call'
railties (6.1.4.1) lib/rails/rack/logger.rb:37:in `call_app'
railties (6.1.4.1) lib/rails/rack/logger.rb:28:in `call'
config/initializers/100-quiet_logger.rb:23:in `call'
config/initializers/100-silence_logger.rb:31:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/request_id.rb:26:in `call'
lib/middleware/enforce_hostname.rb:23:in `call'
rack (2.2.3) lib/rack/method_override.rb:24:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/executor.rb:14:in `call'
rack (2.2.3) lib/rack/sendfile.rb:110:in `call'
actionpack (6.1.4.1) lib/action_dispatch/middleware/host_authorization.rb:92:in `call'
rack-mini-profiler (3.0.0) lib/mini_profiler/profiler.rb:249:in `call'
message_bus (4.2.0) lib/message_bus/rack/middleware.rb:60:in `call'
lib/middleware/request_tracker.rb:202:in `call'
railties (6.1.4.1) lib/rails/engine.rb:539:in `call'
railties (6.1.4.1) lib/rails/railtie.rb:207:in `public_send'
railties (6.1.4.1) lib/rails/railtie.rb:207:in `method_missing'
rack (2.2.3) lib/rack/urlmap.rb:74:in `block in call'
rack (2.2.3) lib/rack/urlmap.rb:58:in `each'
rack (2.2.3) lib/rack/urlmap.rb:58:in `call'
unicorn (6.1.0) lib/unicorn/http_server.rb:634:in `process_client'
unicorn (6.1.0) lib/unicorn/http_server.rb:739:in `worker_loop'
unicorn (6.1.0) lib/unicorn/http_server.rb:547:in `spawn_missing_workers'
unicorn (6.1.0) lib/unicorn/http_server.rb:143:in `start'
unicorn (6.1.0) bin/unicorn:128:in `<top (required)>'
vendor/bundle/ruby/2.7.0/bin/unicorn:25:in `load'
vendor/bundle/ruby/2.7.0/bin/unicorn:25:in `<main>'
Falha ao tratar exceção em middleware de exceção: ArgumentError: número incorreto de argumentos (dado 0, esperado 1)
/var/www/discourse/plugins/discourse-chat/lib/guardian_extensions.rb:71:in `can_rebake?'
/var/www/discourse/lib/guardian/ensure_magic.rb:11:in `method_missing'
/var/www/discourse/app/controllers/posts_controller.rb:570:in `rebake'
actionpack-6.1.4.1/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack-6.1.4.1/lib/abstract_controller/base.rb:228:in `process_action'
actionpack-6.1.4.1/lib/action_controller/metal/rendering.rb:30:in `process_action'
actionpack-6.1.4.1/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
activesupport-6.1.4.1/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
/var/www/discourse/app/controllers/application_controller.rb:397:in `block in with_resolved_locale'
i18n-1.10.0/lib/i18n.rb:328:in `with_locale'
/var/www/discourse/app/controllers/application_controller.rb:397:in `with_resolved_locale'
activesupport-6.1.4.1/lib/active_support/callbacks.rb:126:in `block in run_callbacks'
activesupport-6.1.4.1/lib/active_support/callbacks.rb:137:in `run_callbacks'
actionpack-6.1.4.1/lib/abstract_controller/callbacks.rb:41:in `process_action'
actionpack-6.1.4.1/lib/action_controller/metal/rescue.rb:22:in `process_action'
actionpack-6.1.4.1/lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
activesupport-6.1.4.1/lib/active_support/notifications.rb:203:in `block in instrument'
activesupport-6.1.4.1/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport-6.1.4.1/lib/active_support/notifications.rb:203:in `instrument'
actionpack-6.1.4.1/lib/action_controller/metal/instrumentation.rb:33:in `process_action'
actionpack-6.1.4.1/lib/action_controller/metal/params_wrapper.rb:249:in `process_action'
activerecord-6.1.4.1/lib/active_record/railties/controller_runtime.rb:27:in `process_action'
actionpack-6.1.4.1/lib/abstract_controller/base.rb:165:in `process'
actionview-6.1.4.1/lib/action_view/rendering.rb:39:in `process'
Sim, consigo reproduzir isso, embora eu me pergunte por que nunca encontramos isso antes 
Introduzido neste commit @martin FEATURE: Chat channel statuses (#619) · discourse/discourse-chat@9c158d6 · GitHub
Bom ponto! Acabei de mesclar um PR para corrigir isso: