IOS(iPad) does not support multiple email addresses via a "Submit a Form" button
When a submit button is created, no email address will be displayed in the "To:" field if more than one email address is entered into the URL field. If only one email address is entered, the "To:" field will be populated. Multiple email addresses appear to work fine on PCs and Android devices when the submit button is clicked.
This is an issue for me too. Please fix this bug.