A more detailed explanation of the whole

"A double-spend broke Bitcoin" FUD that was circulated by an irresponsible publication.

1/

There was a chain re-organization in the Bitcoin blockchain. This is a common occurrence that is part of Bitcoin's normal operation. It is a result of decentralized consensus under Proof-of-Work. All PoW chains do this.

2/

Two blocks were mined almost simultaneously, competing for the same height, meaning that they had the same parent block and were trying to extend the chain of the same block

3/

Only one can ever succeed in the long run. It is possible that different nodes and miners see one or the other block first and assume it is the winner. This is also normal in a decentralized consensus algorithm

4/

Eventually, within an average of 10 minutes another block is mined. This new block has as its parent *one* of the two competing blocks. Which one? Whichever one the miner saw first and assumed to be the winner.

The new block extends the chain, resolving the issue.

5/