Just encountered a few graphics errors during the whole Diamond Weapon event in Disc 2 yesterday. Here's one of 'em:
Occurs during the buildup to the Cannon firing, when everyone's still on the Bridge.
There's another one before that, when Diamond is moving towards midgar. The World map is missing textures all over the place. There was one really bad spot when I tried it the other day, with entire landmasses acting as if they'd got Hidden Surface Removal'd.
Later on, when you're trying to get to Hojo, the entire screen, 2D background and all, was totally corrupt, and other 2D artifacts started appearing (improper colors, random border lines around the experience gauges and text boxes, etc.)
I haven't had these errors happen to me when I replayed the scene today, so I don't know if it's from the PRP patch or if my video card started screwing up randomly....