LDAP user don't see assigned devices

As in ticket OBS-1684 described before: I assign users authenticated via LDAP read-only devices. But when them logging in their page is empty. (No device listed)

I tried to assign users to a role, which contains a set of devices, try to assign directly some devices, logged out and logged in again - nothing helps. 

we're using a standard ldap, all users are listed so I have no idea anymore and it looks like a bug.