Longer wait times between finding new blocks can be triggered by the mining pool experiencing a period of temporary bad luck. For instance, if the pool’s current hashrate and the current network difficulty estimate that the pool will discover 1 block every 4 hours, this estimation is only an average. Over the short term, the pool may discover a block just 1 hour after the discovery of the previous one, but then not find another block for several hours after that. It’s important to understand that past luck has no impact whatsoever on the future. Ultimately, luck always averages 100% — balancing the highs and lows.