Hi guys ContraPvP here, In kit PvP you get stacked bottles of potions (eg. Health potions in Kit Emerald.) If you open up your ender chest and stack up the bottles, the potions stack removing one each time. (See screenshot) Not sure if its a bug but it has enabled me to stack 16 level 2 health potions. Thanks for reading. See how I have 18 health pots? There. :)