Proof of stake creates new coins by staking the coins in a persons wallet , and sometimes these stakes are sent to the network at the same time as someone elses . only one person will receive that stake for that specific block and it is written to the blockchain, the other is an orphaned block , there is nothing lost here, the stake rolls over to the next block until it is accepted as can be seen in your picture example. Over time the percentage per year which is currently 7% will average out on your returns.