Why do all the cooktop igniters spark when I only turn on one burner?

This is normal operation — all igniters spark when any single burner control knob is pushed. You should not touch any of the burners when the cooktop is in use. Additionally, when electrical power is first connected or reconnected after an outage, the igniters may spark once or twice even though all knobs are in the off position. (Pages 6, 31)