So first of all, it looks like you placed the note in the wrong place. The spot where the picture was taken is on the exit of the eastbound Dulles access road onto I-495 North. Even with that, I don't see any issues with the data. I'm guessing the car's software is either not parsing the OSM tags properly (assuming it uses OSM data at all), or is using old data. That being said, I don't see any older versions of the data that had exit information that would result in the guidance you witnessed.

Route example: https://www.openstreetmap.org/directions?engine=fossgis_valhalla_car&route=38.9337%2C-77.2301%3B38.9448%2C-77.2030#map=15/38.9372/-77.2165

Overpass: https://overpass-turbo.eu/s/1MPi