https://www.curseforge.com/minecraft/mc-mods/all-stackable/

Reason:
After removal of Charm in 1.3.0 - enchanted books, stews and potions are starting to slowly "expand" over all the empty space in the inventory.

With the following global config, it'll emulate the "stackable" part of Charm as it was in AOF5 1.2.4 (but maybe "permissionLevel" needs adjustment):

[{"minecraft:beetroot_soup":16,"minecraft:potion":16,"minecraft:rabbit_stew":16,"minecraft:mushroom_stew":16,"minecraft:enchanted_book":16},{"applyGlobalConfigToAllNewGames":1,"permissionLevel":4,"stackEmptyShulkerBoxOnly":0}]

Worth noting: default config doesn't change any item stacks.