ObjRef() returns from ray task

[clivelo]

Testing with the example Pandas DAG.

The build_dataframe() does not return the dataframe but instead returns an ObjRef(), which leads to the next task failing.

Task logs showed

[2023-05-30, 08:13:34 UTC] {ray_backend.py:116} INFO - Failed to look up actor with name 'ray_kv_store'. This could because 1. You are trying to look up a named actor you didn't create. 2. The named actor died. 3. You did not use a namespace matching the namespace of the actor.
[2023-05-30, 08:13:34 UTC] {ray_backend.py:118} INFO - Creating new Actor with identifier Failed to look up actor with name 'ray_kv_store'. This could because 1. You are trying to look up a named actor you didn't create. 2. The named actor died. 3. You did not use a namespace matching the namespace of the actor.