Skoda Superb road sign recognition is hit and miss

They do post this as a disclaimer in their manuals , but you could try another dealership whilst it is still under warranty and say what they say . Possibly software update available .

The traffic signs may not be displayed or displayed incorrectly in the system
e.g. in the following situations.
■ When visibility is poor, (e.g. fog, heavy rain, thick snowfall).
■ The sensor is blinded by the sun or oncoming traffic.
■ The field of view of the sensor is limited by an obstacle or a preceding vehicle.
■ Travelling at high speed.
■ The traffic signs are covered (e.g. by trees, snow or dirt).
■ The traffic signs are not standard (round with a red border) or are damaged.
■ The traffic signs are attached to flashing neon signs.
■ The traffic signs were changed (the navigation data are out of date).