Double Odyssey Ziggs shard as reward

So you get one ziggs skin shard just by beating onslaught itself and you can get any odyssey shard by doing the recruitment missions. So why is it a possibility that you can get a dupe odyssey ziggs skin shard? It's a complete waste and its really tilting to see all that time wasted grinding for nothing. There shouldn't be a possibility that you can get the same skin through the mission rewards. It feels now that I wasted so many hours farming the missions for nothing.