I wan to add that this is true for all three door tiles as well: Pneumatic Door,.Manual Airlock, and Mechanized Airlock, and the warning is also displayed on the vacuum when the tiles don't have anything in them.
Airflow tiles when built in space still allow the liquids or gasses in the tile to display the red warning "! Space Exposure" in their status. However, Airflow Tiles, and Mesh Tiles as well do not allow gasses or liquids inside them to escape to space. This is counterintuitive. I suggest that the "! Space Exposure" status for a tile be removed when a airflow or mesh tile is built in that location.