Registration field and Recaptcha - strange error when recaptcha inserted words are wrong

I have enabled submission for public users by creating a registration field and enabling recaptcha

However I just made some tests and I am being redirected to a strange error page both when the words inserted for recaptcha are wrong or right

the error I see is the following

**Error

0!

SQL=UPDATE fgd7_users SET name='',username='',email='',password='',block='0',sendEmail='0',registerDate='0000-00-00 00:00:00',lastvisitDate='0000-00-00 00:00:00',activation='',lastResetTime='0000-00-00 00:00:00',resetCount='0' WHERE**

note that even if I am redirected to that error page, the user is still being created correctly and I receive the welcome e-mail with login details normally,

instead the submitted record is not being created

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