The igniter and valve cycled with the dryer open. Once normal airflow was restored by reassembly, the dryer operated normally.
The same symptom can have a different cause. Short flame cycles in a fully assembled dryer still require vent, sensor, thermostat and gas-path diagnosis.
The discussion attributed the bench behavior to missing designed airflow. Without the complete air path, temperature rose at the sensing point and the thermostat interrupted the burner; the high-limit could open if temperature continued rising.
The explicit normal test after reassembly confirmed that this particular cycling was not corrected by the previously installed coils.
A test is only useful when its setup preserves the conditions the appliance needs. Record whether covers, drum and ducts were installed whenever flame duration is used as evidence. Do not generalize an open-cabinet flame cycle to normal operation.