For anyone having a similar issue, I found the following solution:
Create the following javascript in a separate file…
jQuery(document).ready(function(){
jQuery('.simplemodal-login, .simplemodal-register, .simplemodal-forgotpw').die();
});
Then enqueue it so that it only loads on the login screen (this is in my themes functions.php file):
function _simplemodal_fix() {
wp_enqueue_script( 'simplemodal', get_stylesheet_directory_uri() . '/js/simplemodal.js', array('simplemodal-login', 'jquery-simplemodal'), '', true);
}
add_action('login_enqueue_scripts', '_simplemodal_fix',15);
Someday…