This is a very real bug. I don't know if it's because the ASI is a showing ground speed instead of airspeed, or if it's because the FM is using ground speed instead of airspeed to determine lift. But if you set a strong wind straight down the runway you have to maintain a considerably higher IAS with a headwind than you do with a tailwind when you're on final in order to maintain an appropriate glide path and angle of attack.