Probably something minor but I have an user event script to copy a field value to another field on a sublist but this isn't working when I'm hiding the field I'm copying to. How can I solve this?

Maybe expose the field, set it then hide it afterwards? Bear in mind hiding a field on a sublist hides it for every row.

Yes that's what I'm wanting to achieve. We have a required to only show specific project tasks so I've created a custom field version with that filter and copy the value to the original field. Yet the copy doesn't function when it's hidden