Recently, we’ve had an incident with one of our RPC services on production. The root cause was an issue with a PgBouncer instance going down. Although PgBouncer was eventually restored and became operational, our service remained partially functional until the pods were restarted. In this article, I’ll document the root cause of the issue and how we fixed it, effectively answering the question posed in the title.

https://burakaymakci.com/why-did-the-elixir-application-keep-running-despite-dependency-shutdown/