This is caused by the difference between the hashrate shown in local miners and the hashrate that the pool received when mining under Cuckoo algorithm. To ensure these 2 data are the same, the submitted hashrate is multiplied by a coefficient. The coefficient that F2Pool used is too large but it doesn’t affect the actual mining revenue.
However, for the conveniences of our miners when estimating the revenue, F2Pool will adjust the coefficient from 2019-03-06 so that the hashrate shown on miners and the one that the pool received nearly the same.
Please notice that the hashrate shown in the pool will be decreased after this adjustment and more similar to your hashrate shown on your miner but it will not influence your mining revenue.
Thank you for your understanding!