User created when captcha fails

When testing the CIMY plugin I am noticing that if i include a captcha (either reCAPTCHA or the Securimage Captcha) but don’t fill it out during registration then the form displays the correct “ERROR: Typed code is not correct.” message and shows the form to be still completed – however, the user account gets created so that when the form is completed it then says that the username / email already exists!

http://wordpress.org/extend/plugins/cimy-user-manager/