Golf 4 ATD Fuel Consumption Display

hello,

I'm having a problem with my Golf 4. The fuel consumption display shows very high values when the car is idling. It starts at 8-9 liters per 100km, then after 5 minutes of idling, it shows 20 liters per 100km, and after 15 minutes, it shows 30 liters per 100km.
Since then, I've also noticed white smoke. The fuel consumption display shows completely normal readings while driving.
The measured values and actual consumption are also normal.
Water level is at its maximum, so no water consumption.

Do you perhaps have an explanation for that?

best regards
ristici

Estimate:

The device measures average consumption, not instantaneous consumption.

This means: The car is stationary, the wheels are not turning, but the engine is running. Therefore, the average fuel consumption is constantly increasing because you are wasting fuel without the car moving.

In my opinion, the two things have absolutely nothing to do with each other.

No, it's about the current fuel consumption, and the white smoke is getting worse, especially when the engine is cold.
"The error memory shows no codes, the measured values are okay, the coolant level is okay, the performance is okay, and the actual fuel consumption is also okay. The mass airflow sensor is working properly, the temperature sensor is working properly, and the fuel injectors are also working properly."

I don't know what else needs to be checked.

Best regards,