Sven,
Can you please try to implement latest oxTrust and oxAuth from here:
- https://ox.gluu.org/maven/org/gluu/oxauth-server/4.1.1.Final/
- https://ox.gluu.org/maven/org/gluu/oxtrust-server/4.1.1.Final/
And see how things go?
I got success by using latest ( 4.1.1 ) oxAuth and oxTrust in Cache Refresh + Manage Authentication.