Ikea Tradfri and DMX lagging


my openHAB setup is based on the openhabian image on a raspberry pi 2. For my lighting I use the Ikea Tradfri system with the Ikea gateway. I also use the new DMX binding for my other lamps. I grouped all Dimmer items from the Tradfri and the DMX binding, to dim them at once.
The problem is, when I give the command to dim for example from 0% to 100%. The Tradfri lamps don’t dim simultaneously, they dim in a random order with a delay of about 0.5 sec. At the same time the DMX lamps dim in 2 steps, which are like 0%-35%-100% instead of a smooth fade. When I disable the Tradfri binding the DMX laps fade normally. I used openHAB before with the same setup in a Docker container on a pretty powerful server. On this setup I didn’t had any of these problems.
On the raspberry pi I use the 2.2 snapshot because of the Tradfri security update, in the Docker setup the 2.1 stable.

Did anyone experienced a similar behavior with the Tradfri binding?

Thanks in advance,

I still couldn’t resolve this problem. I tried a completely new setup and got the same result. Has anyone an idea?