Apparently it’s a bug as the documentation states that the Developer Account has permission/authorization to create User Account (Project Members). (see image below).
And this is very important, for security reasons! We need this fix as we will be creating all Devices and User Accounts (Project Members) with the Developer Account instead of an Administrator Account.
Since the username is exposed in the URL, it is safer to create devices and User Accounts (Project Members) with a Developer Account.
We will leave the Administrator Account exclusively to perform Server/Host maintenance.
If we create devices and users (of our customers) with the Administrator Account it would be the equivalent of using the Linux ROOT user for routine activities, which is dangerous.
Is it possible to fix this bug in less than 10 days?