No, I think the "Great Wall Bug" refers to something different:
If a civ has the Great Wall and you bombard a town of that civ (not the town with the Great Wall, another one) and the game decides that this bombardment should destroy one of the towns improvements, then it tries to destroy the city wall, but it can't, because the town does not really have a city wall (it's provided by the Great Wall). The game then crashes.
In Vanilla/PTW this happened quite often, because here the bombardment would first target the town's improvements. In C3C it happens very seldomly, because they inverted the priority (first target are units, and only when all units are red-lined, the improvements become a target).
There is also a similar effect, which happened to me in GOTM98: I had captured the Great Wall in that game, and at one point a barbarian horseman entered one of my undefended towns and the game crashed. Apparently the barbarian tried to destroy the city walls, but as the walls were "undestroyable" (not real walls, but provided by the Great Wall) it wasn't able to, and the game crashed.
I had to reload the game from the auto-save and this time luckily an AI killed the barb before it was able to enter my undefended town.
In another GOTM (can't remember which one) I suffered from the "pure" Great Wall Bug: game kept crashing when I bombarded an AI town. So I had to finish this particular AI without the use of catapults...
I think the same effect can happen with the Pyramids, when bombardment/barbarians try to destroy the "virtual" granary in a town. But have never seen it in my games so far.