With my NVIDIA Geforce 7900 Go card at home I had a similar problem that lasted all of about 2 seconds. Till I read this thread I thought it was a reflection of the light in my room.
Was in Nav Map at around 6000 TC and went straight to Bridge and the glow lasted about two seconds under my bow and went away.
Thats the only time I've had this problem, which at the time I didn't even realize was one.
