I’ve noticed that adding cast members (which I do ALOT) via the custom cast option is a serious pain in the ass when using IOS. Here’s why….
When you try to add a cast member, the character name field is buried underneath the iPhones keyboard so you can’t even see what you’re typing. Also, you can only add one cast member at a time since everytime you add one, the next one you try to add is just buried further deeper down the list that is not visible.