High Oil Consumption: Crankcase Ventilation Issues?

Hello everyone,

I have another question for you, and it's something that's a little concerning.
I recently had my crankcase ventilation system checked and serviced at VW (filter replacement due to crankcase pressure).
After having the entire issue re-examined at VW, I've noticed that the 'Check Oil Level' warning light now appears at regular intervals. I've been observing it closely. Since the oil change, I've had to add at least 250 ml of oil every 500 km. Before that, I drove thousands of kilometers without ever needing to top up the oil!
Could a higher oil consumption be caused by changing the filter? Or did they perhaps forget to verschandeln the filter?
2. Checking the oil level is now essential on any longer highway trip! If I park the car and let it sit for 5 minutes before checking the oil level, it's still within the normal range (b). Unfortunately, this message appears after opening the hood, even though it should be suppressed. I suspect the sensor might be faulty! Does anyone know when this message actually appears? Is there a way to test the oil level sensor to see if it's working correctly (e.g., by measuring the voltage)?

As I said, both of these issues started after I had the crankcase ventilation system installed. Could it be related to that?

Best regards, Manuel.