They both appear in the buff bar. Any reason why they wouldn't stack for a total of +450% droprate?
Yeah they stack if im not mistaken. Golden cotton candy just doesn't stack with similar items, such as Candied Luck or other items that raise drop rates with 50%.
Works the same with 2x/3x/4x exp cards and the 50% EXP event items. They also stack but just not with other 50% event items.