In the 1.8.2 MCX360 changelog, it says cakes were made stackable, but in the PC version cakes are not stackable.
MC-3730
Cakes are stackable in MCX360 but not the PC version
Resolved
Invalid
0
The X360 and PC versions are different distributions of the game, and thus have different features. This is not a bug, but a feature request, and should be posted on the MC forums here.