F2Pool returns about $500,000 in abnormal ETH transaction fee to its sender after encountering the issue on June 11.
Source: https://cointelegraph.com/news/f2pool-returns-500k-of-abnormal-eth-transaction-fee-to-sender
F2Pool Returns $500K of Abnormal ETH Transaction Fee to Sender
June 18, 2020
CoinTelegraph