Cake Stacking?

I was playing a map called 'FunLand 3' (Download the map for yourself at http://www.skydaz.com/funland-3-a-minecraft-amusement-park-map/) and came across a chest full of stacked cakes in 'The Fudgery', which I could then hold and stack up even more, into 105 and more! This is weird, and when I middle click, it still brings out 1, like normal. This is very weird.... I have added 3 pictures below, of the chest, the stacking and of the outside of the shop, if you need to locate it easily. This does not happen on any other item and will only let you hold the 105 if you drop it and pick it up. If you try to replace it, it will put down 64 and you will still hold the rest. I have exited and saved, and this still happens.