Some users may not receive password reset emails sent from your site via Piano. Piano rewrites reset links (for example, www.example.com/reset-password?reset_token=RSTIkINF1qh48jx) so they first go to a Mandrill tracking URL. The link's href differs from the displayed URL, and the emails may not reach the user's inbox.
You can disable Mandrill link rewriting by adding an explicit href attribute to your Piano ID Password reset requests template so Mandrill does not overwrite it, as described here.
After you apply this attribute, Mandrill will stop changing the links. Emails are more likely to be delivered, and recipients will not see scam warnings when viewing the message.