I guess a faulty appliance but while cooking on one ring the others would start by themselves, sometimes with pans on them, burning everything in them!
Other times the whole hob will turn off or just one of the rings cooking. Completely unresponsive. I wish AEG would take care of this instead of keep sending technical service which will not solve it.
Total control over cooking time
The adjustable timer (max. 99 minutes) will remind you of the cooking time. It can also be used as a minute minder when the burners are not in use.