没有进一步的更新，我现在剩下 30 个。我猜它们是超时的，但我的测试帐户收到了（延迟的）每周摘要，我猜这与此有关。不知道在哪里查看日志才能知道是否有任何帐户确实放弃了。
它们似乎大多失败但偶尔会成功，这肯定表明某个地方存在竞态条件。
我的堆栈跟踪看起来与 @RBoy 和 @md-misko 看到的相同，但这是 完整 的堆栈跟踪，而不仅仅是来自“复制”按钮的截断版本：
activerecord-7.0.3/lib/active_record/validations.rb:80:in `raise_validation_error'
activerecord-7.0.3/lib/active_record/validations.rb:53:in `save!'
activerecord-7.0.3/lib/active_record/transactions.rb:302:in `block in save!'
activerecord-7.0.3/lib/active_record/transactions.rb:354:in `block in with_transaction_returning_status'
activerecord-7.0.3/lib/active_record/connection_adapters/abstract/database_statements.rb:314:in `transaction'
activerecord-7.0.3/lib/active_record/transactions.rb:350:in `with_transaction_returning_status'
activerecord-7.0.3/lib/active_record/transactions.rb:302:in `save!'
activerecord-7.0.3/lib/active_record/suppressor.rb:54:in `save!'
activerecord-7.0.3/lib/active_record/persistence.rb:55:in `create!'
activerecord-7.0.3/lib/active_record/relation.rb:869:in `_create!'
activerecord-7.0.3/lib/active_record/relation.rb:115:in `block in create!'
activerecord-7.0.3/lib/active_record/relation.rb:880:in `_scoping'
activerecord-7.0.3/lib/active_record/relation.rb:428:in `scoping'
activerecord-7.0.3/lib/active_record/relation.rb:115:in `create!'
activerecord-7.0.3/lib/active_record/relation.rb:219:in `block in create_or_find_by!'
activerecord-7.0.3/lib/active_record/connection_adapters/abstract/transaction.rb:319:in `block in within_new_transaction'
activesupport-7.0.3/lib/active_support/concurrency/load_interlock_aware_monitor.rb:25:in `handle_interrupt'
activesupport-7.0.3/lib/active_support/concurrency/load_interlock_aware_monitor.rb:25:in `block in synchronize'
activesupport-7.0.3/lib/active_support/concurrency/load_interlock_aware_monitor.rb:21:in `handle_interrupt'
activesupport-7.0.3/lib/active_support/concurrency/load_interlock_aware_monitor.rb:21:in `synchronize'
activerecord-7.0.3/lib/active_record/connection_adapters/abstract/transaction.rb:317:in `within_new_transaction'
activerecord-7.0.3/lib/active_record/connection_adapters/abstract/database_statements.rb:316:in `transaction'
activerecord-7.0.3/lib/active_record/transactions.rb:209:in `transaction'
activerecord-7.0.3/lib/active_record/relation/delegation.rb:67:in `block in transaction'
activerecord-7.0.3/lib/active_record/relation.rb:880:in `_scoping'
activerecord-7.0.3/lib/active_record/relation.rb:428:in `scoping'
activerecord-7.0.3/lib/active_record/relation/delegation.rb:67:in `transaction'
activerecord-7.0.3/lib/active_record/relation.rb:219:in `create_or_find_by!'
activerecord-7.0.3/lib/active_record/querying.rb:22:in `create_or_find_by!'
/var/www/discourse/lib/email/sender.rb:498:in `get_reply_key'
/var/www/discourse/lib/email/sender.rb:105:in `send'
/var/www/discourse/app/jobs/regular/user_email.rb:83:in `send_user_email'
/var/www/discourse/app/jobs/regular/user_email.rb:38:in `execute'
/var/www/discourse/app/jobs/base.rb:232:in `block (2 levels) in perform'
/var/www/discourse/lib/rails_multisite/connection_management.rb:80:in `with_connection'
/var/www/discourse/app/jobs/base.rb:221:in `block in perform'
/var/www/discourse/app/jobs/base.rb:217:in `each'
/var/www/discourse/app/jobs/base.rb:217:in `perform'
sidekiq-6.4.2/lib/sidekiq/processor.rb:196:in `execute_job'
sidekiq-6.4.2/lib/sidekiq/processor.rb:164:in `block (2 levels) in process'
sidekiq-6.4.2/lib/sidekiq/middleware/chain.rb:138:in `block in invoke'
/var/www/discourse/lib/sidekiq/pausable.rb:138:in `call'
sidekiq-6.4.2/lib/sidekiq/middleware/chain.rb:140:in `block in invoke'
sidekiq-6.4.2/lib/sidekiq/middleware/chain.rb:143:in `invoke'
sidekiq-6.4.2/lib/sidekiq/processor.rb:163:in `block in process'
sidekiq-6.4.2/lib/sidekiq/processor.rb:136:in `block (6 levels) in dispatch'
sidekiq-6.4.2/lib/sidekiq/job_retry.rb:114:in `local'
sidekiq-6.4.2/lib/sidekiq/processor.rb:135:in `block (5 levels) in dispatch'
sidekiq-6.4.2/lib/sidekiq.rb:40:in `block in <module:Sidekiq>'
sidekiq-6.4.2/lib/sidekiq/processor.rb:131:in `block (4 levels) in dispatch'
sidekiq-6.4.2/lib/sidekiq/processor.rb:257:in `stats'
sidekiq-6.4.2/lib/sidekiq/processor.rb:126:in `block (3 levels) in dispatch'
sidekiq-6.4.2/lib/sidekiq/job_logger.rb:13:in `call'
sidekiq-6.4.2/lib/sidekiq/processor.rb:125:in `block (2 levels) in dispatch'
sidekiq-6.4.2/lib/sidekiq/job_retry.rb:81:in `global'
sidekiq-6.4.2/lib/sidekiq/processor.rb:124:in `block in dispatch'
sidekiq-6.4.2/lib/sidekiq/job_logger.rb:39:in `prepare'
sidekiq-6.4.2/lib/sidekiq/processor.rb:123:in `dispatch'
sidekiq-6.4.2/lib/sidekiq/processor.rb:162:in `process'
sidekiq-6.4.2/lib/sidekiq/processor.rb:78:in `process_one'
sidekiq-6.4.2/lib/sidekiq/processor.rb:68:in `run'
sidekiq-6.4.2/lib/sidekiq/util.rb:56:in `watchdog'
sidekiq-6.4.2/lib/sidekiq/util.rb:65:in `block in safe_thread'
我还能提供哪些更多信息来帮助调试这个问题？