Villager trades can have more then 64 emeralds

I was trading with a villager and one of the trades was having more then 64 emeralds. Seed: 77778777. Villagers spawned in with cheats.

What I expected to happen was...:
I had a trade less then over a stack.

What actually happened was...:
I had a trade which had more then a stack of emeralds.