Settings not saving

I am trying to disable the automatic description meta tag from being created. Un-checking the option and saving does not seem to work – the setting is still checked on refresh and the meta tag still created on the front-end.

edit: The culprit is found here: (around line 187)

// If missing (eg checkboxes), use the default value
else {
    $add_meta_tags_opts[$def_key] = $def_value;
}

This essentially makes it impossible to save anything but the default values as the checkbox field is not sent in $_POST if not checked.

https://www.ads-software.com/extend/plugins/add-meta-tags/