I have a custom "list/record" field with a type of "item" I have a script that sets that field, but sometimes I need to set it to an inactive item - when the script tries to do that, it throws an error saying I've entered an invalid value. Anyway to work around this?

Once you've inactivated a value, it stays on past records but cannot be used going forward. The root issue is that the item has been inactivated and you're trying to use it. You'd have to re-activate the item or use a diff item.

Your script should be able to pretty quickly check if an item is inactive