EG Attachments can cause error on SSL-enabled site, because it loads CSS file via HTTP regardless enabled HTTPS. To fix this, lib/eg-plugin.inc.php has to be edited:
$this->plugin_url = trailingslashit(WP_PLUGIN_URL.'/'.$plugin_base_path);
And replace with:
This is because WP_PLUGIN_URL is legacy constant that does not take into account SSL. Would be great if author include this with updates.