When I turn on a burner on the left side the igniters keep arcing after the gas comes on until I turn on a second burner on either side. If I turn on a burner on the right side the igniter stops when the gas lights. The started to happen after I had the unit apart to replace the switches for the pop up exhaust vent.
Check the ignition wires connection to the spark module. Make sure the wire from the ignition switch and the wire form the ignition electrode for the same burner are connected to the spark module terminals with the same number.
Here are the breakdown diagrams and Replacement parts for THERMADOR SGCV36G01 COOKTOP | AppliancePartsPros.com
Gene.