Question about Bryan Wilks.

So, recently, I have been replaying fallout 3 (mainly because I never finished the game) and I have run into a problem. I remember that in the past, when I went to the Super Duper Mart for the first time, Bryan Wilks comes running up to me when I leave the mart. But now, he doesn't even show up, and only appears if i get closer to Grayditch. And the reason I have an issue so much with this is because it just kinda ruins the immersion for me.

So, can someone please explain to me why it is not working anymore. Is it based on the time of day? Or what day it is? I just want to know.