Bitcoin mined an empty block at height 871732

ChainCatcher message, according to mempool data, miners mined an empty block at Bitcoin height 871732 (i.e., the block only contains a single transaction for the block reward Coinbase), with only a 6-second interval from the previous block height.

Miners package empty blocks out of economic considerations; doing so is the wisest choice for miners. In order to make full use of this time for mining and to avoid conflicts with transactions packed in the parent block, miners cannot fill the block with transactions, meaning that miners can only attempt to mine empty blocks.