irecruitment external account getting created for internal employees automatically on an adhoc basis

have an unusual occasional occurrance when some external visitor user acount is created by the system automatically for some alcoa employee

the user account is their company email address and the irecruitment external candidate responsibility is assigned

we do not currentl use the external irecruitment functinality so are unable to find out how the accounts are being created - the employee is usually has not done anything

thanks