Hi there,
Power Armor MK2 doesn't have the previous armor in its ingredients. I was able to fix this by rewriting prototypes/recipe.lua to:
table.insert(data.raw.recipe["heavy-armor"].ingredients , {type="item", name="light-armor", amount=1})
table.insert(data.raw.recipe["modular-armor"].ingredients , {type="item", name="heavy-armor", amount=1})
table.insert(data.raw.recipe["power-armor"].ingredients , {type="item", name="modular-armor", amount=1})
table.insert(data.raw.recipe["power-armor-mk2"].ingredients, {type="item", name="power-armor", amount=1})
This is also a better way as you don't set the whole list again. Can you please update your mod?