hello everyone! Today I started receiving this message in a stream:

Crash detected! Execution was interrupted by an unexpected exception: TypeError: no default __reduce__ due to non-trivial __cinit__

We use Prefect Cloud, and a worker (process type) on a small machine on EC2. The only change we made was adding retries in the flow:

@flow(name="flow_name",
       retries=3,
       retry_delay_seconds=30)

Do you know what it could be due to?

https://docs.prefect.io/latest/concepts/results/#persisting-results Enabling flow level retries requires (and enables) result persistence for tasks. Googling your error makes me think that you're returning something from a task that is not pickable by default. Results by default are pickled with https://docs.prefect.io/latest/concepts/results/#pickle-serializer