My board showed 3 tasks running; the profile page said 2 running, 1 queued. Both were right: one card was waiting in line but nothing said so. The queue never refuses a dispatch, so it lives in Postgres rows, not GenServer state: the GenServer is a fast index rebuilt on boot, and a monitored waiter releases its slot in 4 lines of handle_info.

https://t0ha.dev/en/elixir/2026/10/29/genserver-is-a-cache.html