Stamina overrides the minetest.item_eat in minetest.register_craftitem so instead of giving direct hp it instead modifies it's stamina value of the player.
Gapples was designed to affect the direct hp of the player. (Obvious collision)
What needs to change:
We need to detect if stamina mod is installed.
If so we need to figure out some way to bypass stamina's override and directly add hp instead of modifying the stamina. (Major update to all the apples)