Problem after last update, Does not save new customer

Hi,

After the last update, it no longer saves new customer data.
He does create a new user account, but he does not save data such as first name, last name, address, etc.
This happens when I create an invoice and want to add a new customer there.

All information is on the invoice, but this cannot be found in wordpress itself, only the new account but no further personal information.

I have disabled ALL plugins and tested whether the problem would be solved, but the problem is still active.

So it is not related to another plugin

Greetings
Michael