Key takeout
A misunderstanding of the fee unit caused an accidental overpayment of more than $60,000 during the exchanged transaction.
Users confusing SAT/VB (price per part-time) with total Satoshis, leading to extreme overpayments.
RBF replaces transactions with expensive versions, while CPFP adds new transactions to enhance the original. Each has its own use cases and risks.
We use reliable wallets, double check fee units to suggest the best rates for your wallet. Avoid panic, stay updated and always check the transaction before pressing “Send”.
Around 00:30 UTC on April 8, 2025, Bitcoin users attempted to use Alternate Buys (RBFs) to promote pending transactions. But instead of the modest bump, their wallets accidentally spent 0.75 bitcoin (BTC).
How does this happen? More importantly, how can you prevent it from happening to you?
Let’s break it down.
Why did Bitcoin users end up paying $60,000?
Users wanted to use Bitcoin’s RBF feature to send 0.48 BTC (approximately $37,770 at the time). This feature allows you to resend transactions at a higher price if your member (waiting room for unconfirmed transactions) is packed with original items. In this case, things weren’t going well and were very wrong.
Timeline:
First transaction: sent at standard fees and not high enough to check immediately.
First RBF attempt: Doubled the fee and changed the recipient (output) address.
Second RBF attempt: I added a massive hespent transaction output (UTXO) of about 0.75 BTC, but I forgot to redirect the changes to my address.
result? That 0.75 BTC was treated as a fee and sent to the miners.
Anmol Jain, vice president of investigatives at Crypto Forensics Firm Amlbot, told Cointelegraph that users are likely to start with “default or conservative” transaction fees. After that, there was a mistake. It confuses how fees are measured.
With many Bitcoin wallets, you can set your rates in one of two ways.
Satoshi’s total fee (minimum Bitcoin unit, such as cents up to $1)
Price per virtual part-time job (SAT/VB). This measures how “heavy” a transaction is in data terms
According to Jain, this is where things went wrong:
“The system is read as a total fee of 30 SATs, but since this is too low, I think it means user type 30.5 SAT/VB.
Simply put, users may have seen a warning that the fees are too low, with only 30 total SATs being too low for transactions to be processed quickly. So, trying to fix it, they might have thought 305,000 means “30.5 SAT per bit”.
However, instead of moderately adjusting the fees, the wallet used it as 305,000 SAT per bit. This was blown away beyond all norms, resulting in losses of over $60,000.
Why is it important?
This highlights that slight confusion between fee units can lead to huge losses, especially when entering numbers quickly manually or using advanced wallet settings without fully understanding them.
Therefore, if you have adjusted your Bitcoin fee, double check the units you set up. As this costly mistake proves, whether it’s “total SATS” or “SATS Per Byte”, there’s a world of difference.
Did you know? In September 2023, users paid a $500,000 fee for a single BTC transaction. It turns out to be an error from Paxos, a Crypto infrastructure company.
Per Exchange (RBF): What is it?
Bitcoin transactions are not final until they are added to the block. If the transaction is stuck, you can resend at a higher fee using RBF to encourage miners to pick up faster.
According to the Bitgo Developer Portal, it was originally proposed by Bitcoin creator Nakoshi Satoshi, and later officially officially by developer Peter Todd as “opt-in RBF”.
How it works:
Enables RBF when sending the original transaction.
If the transaction remains unconfirmed, you can create an exchange at a higher price.
Miners may opt for a higher-priced version as they are financially encouraged.
But here’s the catch. If you ruined the inputs and outputs, especially the change address, it could cost you.
In particular, RBF differs from Child Payment (CPFP) in that it replaces the original, unconfirmed transaction with a higher-value version, and only the sender can start it. In contrast, CPFP adds high-price child transactions to increase parental confirmation and can be initiated by the sender or receiver.
Why did Bitcoin trading fees skyrocket?
In this case, there are several theories behind what caused the absurd fees.
Confusion over fee units: Misunderstandings about fee units may have caused fees to skyrocket. Instead of setting a reasonable rate per byte, users may be incorrectly entering a large absolute value, which will cause the wallet to apply excessively high prices.
Automation is incorrect: If your wallet uses automated scripts, or if there is a bug in how RBF handles it, you can either misread the user’s input or, worse, run it without proper warning.
Why RBF is controversial
The RBF feature has sparked years of debate within the Crypto community. It helps to fix stack transactions, but critics like Mike Hearn (formerly Bitcoin developer) have argued about the medium.
It allows double spending attacks, especially for in-person merchant transactions.
Encourage Miner-Fraudster’s conspiracy.
Adds complexity and allows for user errors.
It can replace unconfirmed transactions, which undermines finality.
To address this issue, for example, Bitcoin Cash (BCH) has removed RBF support and states that unconfirmed transactions are final. However, depending on how Mempools works, similar RBF-like alternatives can occur in BCH.
Did you know? In November 2023, 139 BTC transactions (equivalent to millions) included a fee of $3.1 million.
How to protect yourself from high Bitcoin trading fees
You don’t need to be afraid of RBF, but you need to respect it. Here are some tips to avoid the next virus charge:
Choose a secure Bitcoin wallet with transparent pricing options. Choose a reputable Bitcoin wallet that clearly shows and explains the type of fee.
Understand Bitcoin Fee Units Before Submitting: Learn the difference between sat/vb (Satosh per Virtual Byte) and total atoshis to avoid accidental overpayments.
Always double-check the transaction before checking. Please check the recipient’s address, fee amount and change address to avoid incorrect use as a mine fee.
Especially if it’s new, try suggesting a fee for your wallet. Most wallets offer dynamic pricing recommendations based on network congestion, so use them instead of manually entering values.
Test it with a small bitcoin transaction.
Monitor Bitcoin Network Fees in Real Time: Use websites like mempool.space to view current rates and choose the best time to submit your transaction.
Don’t avoid slow checking: Bitcoin transactions can take time. Unless you’re sure you need it, you should refrain from trading or wait before replacing it.
Please let us know about wallet updates and bugs as software bugs and interface changes may affect how fees are calculated or displayed.
Skip the above precautions and you can pay hundreds or thousands of dollars at unnecessary fees without a way to recover your losses. When it comes to Bitcoin, one small mistake can be a costly lesson.
This article does not include investment advice or recommendations. All investment and trading movements include risk and readers must do their own research when making decisions.
