That's interesting. A trip to the dermatologist may shed light on this. Did you ever have a bald spot there? When hair grows in, it can look like that short bit of hair for a very long time. Unfortunately they do say that when hair stops growing in just one spot, it is a sign of alopecia. But this sounds a bit different. It's impossible to say without seeing it. What is the skin like where the hair is?
Did you ever make it to the dermatologist to see what is going on with this? Let me know any update