Usernames change when you change a user group

Usernames change when you change a user group

If I give a customer a different user group in Joomshopping, his username is changed to his email address, i.e. from that moment on he has to log in with the email address instead of the username, also in the Joomla user management the email address is displayed instead of the username from that moment on.

I use Joomla 4 and Joomshopping 5 with the addons Individual text for update order status, User Synchro and User groups discount for category.

Aw: Usernames change when you change a user group

http://j4/administrator/index.php?option=com_jshopping&controller=config&task=fieldregister
configuration / Fields Registration ?

Joomshopping 5.1.0?

url?
admin login?
(forum privat msg.)

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