Plugwise device discovery issues

[markvdm]

I have 2 plugwise devices installed. Both device are in a very close range to the stick.
Although all works fine in the source, Domotiga has difficulties to find the devices upon startup. Sometimes the circle+ device is found, sometimes only the circle is found.

Is this something related to the DomotiGa software? What could I do to make the setup somehow more reliable?