attached url not working with tag

Hi,

I am trying to create a link to an attached pdf. The following code works with the exception of when i attempt to put the [field url] within an tag. In this case it returns the post URL and not the attachment URL. Can you help ?

Thanks, Dean

[if attached]
    [attached]
    [-if field=url end="pdf"]
    [field url]</br>
    <a href="[field url]" target="_blank">PDF</a>
    [-else]
        This post has no PDF attachments
    [/-if]
    [/attached]
[else]
    This post has no attachments.
[/if]

https://wordpress.org/plugins/custom-content-shortcode/