We use ODK for a regular collection of records about patients care, car use, etc. It works perfectly. The whole agenda is driven by a central application that takes records about all necessary entities (forms, patients, employees, cars, etc.) and controlls all the processes.
Employees (data collectors) are created in this application and it then needs to create them in ODK in order to allow them to work. It also generates a QR code from the ODK Collect config with customized settings (e.g. autosend of completed forms, autoupdate of forms, hiding of specific buttons, etc). I found out that ODK Central generates the ODK Collect config in such a form that it does not use authentication buth rather some specific key in the server URL and I also foun out that this key corresponds to the "token" of the created app-user.
So I have in fact already resolved this topic and I can generate customized config QRs myself.
But the other topic remains unresolved - why the same XML form (also generated from the application) is correctly processed in ODK Aggregate and is causing error in ODK Central (and Collect)?