What do you think would happen if I took the same exact part out of a Toyota engine and tried it in a Honda engine? Might work, might not, depending on the part.
The PS3 and XBox are different consoles with different hardware and different operating systems. The exact copy of the game should work the same on both consoles, and most of the time, with most games, they do. But the fact that they are different consoles with different hardware and different operating systems shouldn't make it that surprising that we see glitches on one system or the other that we don't see on the opposite system.