UPDATE: Further analysis from blockchain analytics site Amberdata suggests yesterday’s abnormal mining rewards were likely a result of a buggy bot.

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Cryptocurrency mining pool Sparkpool has said it is temporarily freezing a mysterious 2,100 ether payment it received Tuesday and is waiting for the sender to reach out for a solution.

The transaction was received as an apparent reward for mining just one block on the ethereum blockchain, but the amount is roughly 600 times the network’s standard block reward.

The company notified its collective of miners in a statement on Wednesday that it will hold the ether – currently worth around $300,000 – for now, in case the abnormally high mining fee was attached in error.

“Sparkpool has recently mined a block with a 2100 ETH mining reward, which was an anomaly that triggered our internal emergency mechanism,” the company said in a statement. “We have temporarily frozen this fee and are now waiting for the sender to contact us for a solution. If the sender does not reach out in the next a few days, Sparkpool will then allocate the fees to miners who are entitled for the reward.”

Xin Xu, CEO of Sparkpool, told CoinDesk via WeChat that the pool is holding the funds given the significant amount involved, and that the firm’s users and miners understand the decision.

Xu added:

“Unfortunately, and fortunately, blockchain is so far not completely run by machines; human are still involved. So we have an opportunity to correct the problem. Integrity is our pool’s priority.”

Sparkpool received the 2,100 ETH payout after mining block number 7,238,290 on the ethereum blockchain.

Since then, users have suggested such activity could be a random fluke when one or perhaps several users accidentally attached abnormally high transaction fees to their payments. Others said it could also be goodwill from anonymous supporters of the ethereum mining community, or even an attempt to launder money via the world’s second largest public blockchain.

Possibly ‘a programming error’

However, subsequent analysis by blockchain analytics site Amberdata suggests yesterday’s abnormal block payout was “likely an automated bot that went wrong.”

Speaking to CoinDesk, CTO of Amberdata Joanes Espanol explained:

“I don’t believe it to be an attempt at money laundering, because the same ‘error’ happened five times within a couple hours, and different mining pools were the lucky recipients of the transaction fees.”

As shown on Amberdata’s blockchain explorer, four other transactions – outside of the one paying out 2,100 ETH – rewarded miners a combined total of roughly 1,890 ETH.

They occurred on block number 7,238,273, 7,238,275, 7,239,023, and 7,239,021. The first three of these transactions as listed were paid out to mining pool Nanopool and the fourth to Ethermine.

What’s more, Espanol highlights that all five transactions including the one paid out to Sparkpool all “originated from the same wallet, which saw their overall balance go from 4,000 to about 400 ETH, for what seems to be a programming error.”

“Yet another good example of why auditing and battle testing smart contract code is vital,” concluded Espanol.

Editor’s note: Xin Xu’s statements have been translated from Chinese.

Ethereum token image via Shutterstock