Also, if I run the following:

import yaml
yaml.dump(node_function(INPUT).to_dict(), open("charles.yml", "w"))

No error happens

This one is a bit weird - it's not really a Kedro issue, what are you trying to achieve here?

I wanted to have a node output YML instead of CSV

Okay you can use

yaml.YAMLDataSet

in your data catalog, you don't need to use the yaml library yourself

My point when showing this was that

oh sorry I got mixed up with the messages

yet it would NOT when i ran it locally

👍