You are using WinCC in combination with SIMATIC Logon.
An error has been discovered in the English WinCC documentation in the following path.
"WinCC Information System > Working with WinCC > Creating a User Administrator > WinCC Options for the User Administrator > SIMATIC Logon Option > Notes on Connecting WinCC/PCS7-OS"
As from WinCC V6.2 SP2, the behavior regarding which user rights a user has who belongs to multiple Windows user groups of which several are stored in the WinCC User Administrator is described incorrectly in the English documentation.
Rights of the logged-on user:
If the user belongs to one or multiple Windows user groups of which several are stored in the WinCC User Administrator, the rights of all these groups are assigned to that user.