Multiple confirmation email at registration

Hello,
I use the CB antispam plugin.
In the facts :
In invisible recaptcha mode. During a new registration caused the sending of more than 100 emails when the registration is set on corfirmation by email but not on validation by a modo. By changing to another mode and leaving the confiramtion by email, it normally works A single email sent.

in parallel I use a Joomla form with the invisible Joomla captcha, it still works well.

No idea what to suggest. Have retested the reCaptcha Invisible mode in CB AntiSpam on my existing developer install and on a fresh install with no issues. I don't see how it could even possible cause this as it will interrupt registration before any emails are sent if its validation fails. My guess is you've a conflict coming from somewhere; possibly due to using Joomlas reCpatcha Invisible which likely is acting on the Joomla user store that happens before CB user store in which case it might be best to set the captcha mode in CB AntiSpam to Joomla so it uses your Joomla captcha plugin.