Make sure when you are removing the associations, and if the device is battery operated, to wake it during removal so it actually removes the association. I was running into that problem on my Z-Wave multi-sensors that got associated with all the Z-Wave lights in my house.
I had a lot of switches that had the extra Unknown Node (255: (0 ? 255.0 : 255)) group association. Interestingly the switch in question did not have this extra association. I removed all the 255 associations for good measure. I’ll have to monitor it to see how things go.
I have the issue again after updating to 0.98.2. This change of association is clearly happening when updating Home assistant.
This time I have dual assocoations (both with entry door sensor and garage door sensor. Therefore every time we open the garage door or the entry door the rollers of the house go up and down and the lights switches on - rather spooky!
The removal of the broadcast group as described above does not work anymore for an unknown reason.
I have disconnected the Garage door sensor - not the most optimal solution, but really needed as the opening and closing of the shutters was extremely annoying.