When you create a new user in the user management but the password is not strong enough – and gives you this error:
An error occured during the request. Unable to proceed.
Password is among the 1,000,000 most common ones. Please make it unique.
Then all the fields you put in with the user details are also emptied. Actually, everything should stay like it is, even the password, with focus being in the field.
(Also, the first line of that error is not informative and very technical – it does not need to be shown.)