If I create a new user via the admin screen, they receive the email fine but when they click on the link, they are presented with a "Failed to verify email address" message. The verification code is in the box but clicking the button still fails to validate them. I also note that the URL is malformed as the & is coming through as an &

There is no entry in the yaf_CheckEmail table for the user and their entry in the yaf_prov_Membership has the IsApproved value set to False.