There’s nothing unexpected here — desktop Safari’s new confirmation prompt appears when a mailto:
link opens from a new tab. AddToAny’s new tab prevents the current page’s tab from getting replaced by a web-based emailer.
Without AddToAny’s new tab, major browsers including Chrome and Firefox will replace the current page to open your default web mailer (Gmail, Yahoo, Outlook.com, etc.).
Alternatively, you’re welcome to add your own custom email service to the plugin if you don’t care about the current page’s tab getting replaced by web-based mail handlers. For example:
function addtoany_add_services( $services ) {
$services['my_mailto'] = array(
'name' => 'Email link',
'icon_url' => 'https://static.addtoany.com/buttons/email.svg',
'icon_width' => 32,
'icon_height' => 32,
'href' => 'mailto:?subject=A2A_LINKNAME&body=A2A_LINKURL',
'target' => '',
);
return $services;
}
add_filter( 'A2A_SHARE_SAVE_services', 'addtoany_add_services', 10, 1 );
See “How can I add a custom standalone share button?” in the plugin FAQs.