According to mempool data, miners mined empty blocks at Bitcoin height of 855858 (that is, the block contains only one transaction with block reward Coinbase), which is only 9 seconds away from the previous block height. Miners pack empty blocks for economic reasons, and this is the smartest choice for miners. In order to make the most of this time for mining and avoid conflicts with the transactions packaged in the parent block, miners cannot fill the block with transactions, which means that miners can only try to empty the block.