Pain point · Reliability & bugs · Blocks work
Completed flow crashes after concurrency lease renewal fails
3 source threads · first seen 2023-01 · last seen 2025-10
Summary
On 3.4.20 a flow whose tasks all finished ends as Crashed after a lease renewal failure terminates execution.
Evidence
Excerpts are copied word for word from the source; follow the link to read it in full.
“Concurrency lease renewal failed - slots are no longer reserved. Terminating execution to prevent over-allocation”
“It never happened when we were running on prefect agent and started appearing after migration”
“If the job is running for more than 4hrs, flow in prefect is marked as crashed after 4hrs + 1-4 minutes”