Location services and Microcells?

It seems that sometime after jb-ing, my iphone4 has lost the ability to determine it's location while connected to an AT&T microcell. (in any app) I'm about 40mi south of downtown Los Angeles, but it thinks I'm smack dab in downtown. Off the microcell, it works fine, and a 3GS on stock ios4 works fine on the same microcell.

Anyone else see this?

 

Yes, seems to have happened after... for a while, I could get another app to "Find" me, which made it work in Maps, but no longer. I'm fully up to date.