The bitcoin network is in a race condition
Yesterday around noon, Bitcoin nodes around the world were temporarily split as two competing miners added block 591,848 to the chain tip at the same time. As you can see from the above thread, BitMex Research was hot on the case doing a great job of following the split while educating Twitter users about the nature of chain splits and how they are resolved.
Yesterday's split resulted in no double-spends and one miner officially losing out on the block reward as other miners decided to build on top of the block mined by the other. Extending the chain tip, causing all of the nodes on the network to coalesce around that chain. Unfortunately for 7 individuals, their transactions which were thought to have had one confirmation turned out to have zero and were then included in the next block. Not really too much of an inconvenience at the end of the day.
This is certainly nothing to fret over as these chain splits are not that uncommon. This is a great moment to reflect and bask in the beautiful glory of consensus via Proof of Work being tested in the wild. Bitcoin works!
Final thought...
Traffic is a terrible thing. Maybe the worst thing.