Bug on datepicker in register form

Hello,

I have a big issue on the register form of my website.
Customers can’t create account (so can’t buy) because the birth day date picker doesn’t work (please see this capture: https://ibb.co/M8VczYv)
Indeed, when we choose a date on the date picker the date format is wrond because their is a “F” inside the date.
This registration form looks deeply linked to angopay for woocommerce plugin as when i desactivate it, the register form only asks email and password

1/ How can i customize this form and remove birthday fiel ?
2/ Please could you have a look and fix this point. It’s very urgent.

Thanks for your investigation

Regards,
Nicolas

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