I am having an issue with one of the simmer enabled burners on my Thermador range (PRG364EDH). With the knob turned off, periodically the stove makes a clicking noise like a solenoid is turning on (same as normal when the simmer feature is used) and begins to spark as though it is trying to reignite just as you would expect in a normal XLO on/off sequence. No gas is flowing as the control knob is turned off. If I turn on the gas knob during the sparking, the burner ignites then shuts down as though it were stuck in the XLO setting mode. If I try to turn on the burner other than when the sparking starts, nothing happens (no gas or spark). It's as though the burner is stuck in the XLO mode as this sequence is continuous even with the gas knob off. The other simmer burner works normally. Thanks for any suggestions you might offer.