Fast difficulty adjustment can lead to perverse incentives giving rise short periods of turbo mining. This results in long (>30 min) periods of no blocks which makes it frustrating for users moving coins. We can disincentivize this behavior with only small impact to steady miners.
This patch introduces an optional Avalanche post-consensus policy called Early Blocks Penalty. The scheme is simple: A difficulty penalty is applied to blocks that arrive within the penalty window from the previous block. If the block hash is not better than this new target, the block will be parked. Avalanche will determine finality.