The frequency of getting that last candy tile on the wheel is likely because there's a 50% chance to get candy and whenever you DO get it, it just displays as that last tile.

I mean, when was the last time anyone got 5 candies from any of the other tiles? The most likely explanation is that the game just shows that last candy tile whenever you get 5 candies.

Half the tiles are candies (not including the super-rare emblem tile) so the game's likely just programmed as "50% chance to get a candy. If person gets a candy, display the wheel landing on that last candy tile".