Hi @angus, there seems to be a bug with latest Discourse:
StandardError (Attempting to access a non preloaded custom field, this is disallowed to prevent N+1 queries.) /var/www/discourse/app/models/concerns/has_custom_fields.rb:158:in `[]'
/var/www/discourse/app/models/concerns/has_custom_fields.rb:158:in `[]'
/var/www/discourse/plugins/discourse-events/plugin.rb:69:in `events_enabled'
/var/www/discourse/plugins/discourse-events/plugin.rb:52:in `block (2 levels) in activate!'
(eval):31:in `_fast_attributes'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:468:in `rescue in attributes'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:455:in `attributes'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:480:in `_serializable_hash'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:359:in `serializable_hash'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer/associations.rb:124:in `block in serialize'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer/associations.rb:123:in `map'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer/associations.rb:123:in `serialize'
/var/www/discourse/lib/freedom_patches/ams_include_without_root.rb:55:in `include!'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:368:in `block in include_associations!'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:367:in `each_key'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:367:in `include_associations!'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:362:in `serializable_hash'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:347:in `as_json'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/json/encoding.rb:35:in `encode'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/json/encoding.rb:22:in `encode'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/core_ext/object/json.rb:41:in `to_json'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/active_model_serializers-0.8.4/lib/active_model/serializer.rb:331:in `to_json'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/multi_json-1.13.1/lib/multi_json/adapters/oj.rb:40:in `dump'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/multi_json-1.13.1/lib/multi_json/adapters/oj.rb:40:in `dump'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/multi_json-1.13.1/lib/multi_json/adapter.rb:25:in `dump'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/multi_json-1.13.1/lib/multi_json.rb:139:in `dump'
/var/www/discourse/app/models/site.rb:123:in `json_for'
/var/www/discourse/app/controllers/application_controller.rb:523:in `preload_anonymous_data'
/var/www/discourse/app/controllers/application_controller.rb:350:in `preload_json'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:426:in `block in make_lambda'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:198:in `block (2 levels) in halting'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/abstract_controller/callbacks.rb:34:in `block (2 levels) in <module:Callbacks>'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:199:in `block in halting'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:513:in `block in invoke_before'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:513:in `each'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:513:in `invoke_before'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:131:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/abstract_controller/callbacks.rb:41:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_controller/metal/rescue.rb:22:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/notifications.rb:168:in `block in instrument'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/notifications/instrumenter.rb:23:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/notifications.rb:168:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_controller/metal/params_wrapper.rb:256:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activerecord-5.2.2.1/lib/active_record/railties/controller_runtime.rb:24:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/abstract_controller/base.rb:134:in `process'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionview-5.2.2.1/lib/action_view/rendering.rb:32:in `process'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-mini-profiler-1.0.2/lib/mini_profiler/profiling_methods.rb:78:in `block in profile_method'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_controller/metal.rb:191:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_controller/metal.rb:252:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/routing/route_set.rb:52:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/routing/route_set.rb:34:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/journey/router.rb:52:in `block in serve'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/journey/router.rb:35:in `each'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/journey/router.rb:35:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/routing/route_set.rb:840:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-protection-2.0.5/lib/rack/protection/frame_options.rb:31:in `call'
/var/www/discourse/lib/middleware/omniauth_bypass_middleware.rb:32:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/tempfile_reaper.rb:15:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/conditional_get.rb:25:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/head.rb:12:in `call'
/var/www/discourse/lib/content_security_policy/middleware.rb:12:in `call'
/var/www/discourse/lib/middleware/anonymous_cache.rb:214:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/session/abstract/id.rb:232:in `context'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/session/abstract/id.rb:226:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/cookies.rb:670:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/activesupport-5.2.2.1/lib/active_support/callbacks.rb:98:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/debug_exceptions.rb:61:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/logster-2.1.2/lib/logster/middleware/reporter.rb:30:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/railties-5.2.2.1/lib/rails/rack/logger.rb:38:in `call_app'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/railties-5.2.2.1/lib/rails/rack/logger.rb:28:in `call'
/var/www/discourse/config/initializers/100-quiet_logger.rb:16:in `call'
/var/www/discourse/config/initializers/100-silence_logger.rb:29:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/actionpack-5.2.2.1/lib/action_dispatch/middleware/request_id.rb:27:in `call'
/var/www/discourse/lib/middleware/enforce_hostname.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/method_override.rb:22:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rails_multisite-2.0.6/lib/rails_multisite/middleware.rb:24:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/sendfile.rb:111:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-mini-profiler-1.0.2/lib/mini_profiler/profiler.rb:171:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/message_bus-2.2.0/lib/message_bus/rack/middleware.rb:57:in `call'
/var/www/discourse/lib/middleware/request_tracker.rb:163:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/railties-5.2.2.1/lib/rails/engine.rb:524:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/railties-5.2.2.1/lib/rails/railtie.rb:190:in `public_send'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/railties-5.2.2.1/lib/rails/railtie.rb:190:in `method_missing'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:68:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:53:in `each'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:53:in `call'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/unicorn-5.4.1/lib/unicorn/http_server.rb:606:in `process_client'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/unicorn-5.4.1/lib/unicorn/http_server.rb:701:in `worker_loop'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/unicorn-5.4.1/lib/unicorn/http_server.rb:549:in `spawn_missing_workers'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/unicorn-5.4.1/lib/unicorn/http_server.rb:142:in `start'
/var/www/discourse/vendor/bundle/ruby/2.5.0/gems/unicorn-5.4.1/bin/unicorn:126:in `<top (required)>'
/var/www/discourse/vendor/bundle/ruby/2.5.0/bin/unicorn:23:in `load'
/var/www/discourse/vendor/bundle/ruby/2.5.0/bin/unicorn:23:in `<main>'
Although running in safe-mode does not fix it!
I guess this one is gonna help…
https://github.com/discourse/discourse-solved/commit/8b8512e73ecac2084adc63a492b9f9f52f1f9a1d