It’s possible the flow run was loaded before its state populated in the database. I imagine a refresh would resolve that unless that flow run specifically is stuck in a weird state.

I'm getting Slack notifications, and they tell me the flow run above actually succeeded.

OHHHHH, I see. I'm running the flow locally, so of course the flow run doesn't actually exist. 😄

So the issue is that the Slack notifier generates a link to Prefect Cloud, even if the flow was being run locally.