Topic: "This transaction has been flagged as replace-by-fee ( RBF )" (Read 4762 times)

Are you talking about the 0.034 BTC sent to 1MqkJQhBYuf48yGinwfeD7aKNBhbm5EAbM in this transaction?
f3b05bd4c4df08c4f64ac6a0d945ccb2bec4a494d16a7981325e451b81d7d08b

If so, then it just confirmed now.  Your wallet only included a fee of 120 satoshis per byte when it built and broadcast the transaction.

According to this website: https://bitcoinfees.21.co/
the recommended fee for fast confirmation is 180 satoshis per byte.

That's why you had to wait.  You needed to wait for a charitable solo miner or mining pool to include your cheaper transaction instead of a higher paying one that would increase their profits.  It looks like Antpool was nice enough to do that for you.

What wallet did you use to send the transaction?  Did you adjust the fee for fast confirmation when you sent it?

Yes, and transactions can be double spent even if they are not marked as RBF.
Read this: https://bitcoin.org/en/you-need-to-know#instant about confirmation and how many of it is required.

If you see your transaction as confirmed on blockexplorers (or in your wallet if you run a full node, or SPV wallet with enough confirmation) then that is their service problem that has not yet updated. Possibly their wallet is not synced with the network.

Once it is confirmed (especially once it is over the 5-6 confirmations) nothing is going to change that transaction in the blockchain... that is the whole point of the blockchain.  The warning is really for people who are happy to accept zero-confirmation transactions and provide goods and/or services without waiting for at least 1 confirmation.

If the transaction is marked as RBF and IF it still has zero-confirmations, there is a possibility that the person who sent it could then resend the transaction with a higher fee, sending the money back to themselves (or someone else) and hope that a miner includes that transaction in a mined block first.

On the plus side, "RBF" is a useful way for people to be able to help shift stuck transactions... if they had used a stupid low fee of like 10sats/byte and it was stuck in the mempool... they could effectively redo the transaction with a 160sats/byte fee to try and help it get confirmed.

The idea being, if a transaction is RBF and not from a trusted source, DON'T trust it until gets at least 1 confirmation.

Your transaction to your exchange is probably just unconfirmed because the network is crazy busy right now... loads of unconfirmed transactions. I doubt it has anything to do with the RBF transaction. I hope you used a decent fee for your transfer to the exchange.  

Thank you for the clarification.

The transaction confirmed yesterday - as of this moment it has about 67 confirmations.

You said the transaction can be replaced - it can only be replaced if it hasn't gotten any confirmations, right? I am asking, because I sent a btc transfer to my exchanger after I received this transaction, and even though the incoming transaction has long been confirmed, my transfer to the exchanger is still pending with 0 confirmations for about 13 hours now.

It means the person who sent that transaction can change the fee of that transaction and send a new one (the transaction is replaceable).
And as always an unconfirmed transaction is still an unconfirmed transaction and unsafe and you should wait for appropriate number of confirmation.

Read details here:
https://bitcoincore.org/en/faq/optin_rbf/

A customer of mine sent me a Bitcoin transfer, and for the first time ever, I saw a transaction message stating:

This transaction has been flagged as replace-by-fee ( RBF )

What does this mean? The transaction has a fairly high miner's fee ( 169 sat/b ), but this message baffles me. Is there a problem with the transaction itself?

The ID is 9ac722ca8177a5528e945c081d5d9b021f91d4687838e66c82e7b4589173a88e

Please elaborate - is there anything I should be worried about?