Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I've had this happen as well. Cydia changed to the same icon as Numba and another one of my jailbroken apps changed to the same icon as AP Mobile. It's not all that annoying but I'm curious as to why they changed.
 
I had it happen to me, 1 app from app store took on icon of previously deleted app store icon.

There is an update to Cydia this morning, I just ran it. Hope it fixes this.

Update: The Cydia update seemed to take care of the problem for me.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.