@gamoxristos have you found the solution for this case?
today I got the problem too. I'm using jessie with raspberry 3.
the problem happened when I replace the temperature sensor with the new one with the same model.
i have tried the command:
sudo rm /etc/webiopi/devices.json
sudo service webiopi restart
in the android the layout is clean, but in the website still show too many icons. I have tried to reboot, shutdown. but it was not helped.