Today's washer fluids contain isopropyl alcohol as their antifreeze - so that's the typical odor - but I don't know what "very weird" means relative to that. In an Audi shop this is usually dispensed from large containers as it's used across the range. A little overfill will often evaporate near the normal cabin ventilation pickups so there's a good chance upon fill that some odor would get inside for a few cabin air changes. If you've had a recent service this is entirely possible, but if your service was in January and you're just now getting an odor, I would rather suspect one of the tubing connections to your hood or pump has come loose or broken (really unusual) and when you use the washers, this leak will also get into your cabin vents. This might also explain why the level has dropped off so relatively quickly. The top off is a normal thing for about every service of the car.