Association Group not set on Qubino DIN Rail dimmer

I want to retrieve updates from momentary switches connected to the qubino dimmer. So i tried to set my controller as a member of association group 1. But short time after setting it, the group will be empty again. In the log files it seams, that association_set does not work correctly, because association_get and association_report after that are empty.

How can I upload a csv log file here?

regards, Falk