How is this "unconfirmed" transaction possible?

[Bit_Happy]

Summary
Size    799 (bytes)
Received Time    2014-08-26 16:09:29
Included In Blocks    317590 (2014-08-26 16:11:42 +2 minutes)
Confirmations    0 Confirmations
~source

It was included in block #317590, roughly 53 blocks ago, but is still saying "0 Confirmations"
It's not causing me any problems, but certainly looks odd:
How is this "unconfirmed" transaction possible?

[1714636184]

1714636184

[Keyser Soze]

Summary
Size    799 (bytes)
Received Time    2014-08-26 16:09:29
Included In Blocks    317590 (2014-08-26 16:11:42 +2 minutes)
Confirmations    0 Confirmations
~source

It was included in block #317590, roughly 53 blocks ago, but is still saying "0 Confirmations"
It's not causing me any problems, but certainly looks odd:
How is this "unconfirmed" transaction possible?

It's an issue with Blockchain.info. For example, blockr.io shows the transaction correctly.

[itsAj]

blockchain.info is showing that it was included in two blocks with the same block number with the block times one minute apart. It is likely the first block was orphaned, then the TX was confirmed in the 2nd block.

[BitsBitsBits]

blockchain.info is showing that it was included in two blocks with the same block number with the block times one minute apart. It is likely the first block was orphaned, then the TX was confirmed in the 2nd block.

WoW, I didn't even know blocks could still be orphaned at this day and age.

[dserrano5]

WoW, I didn't even know blocks could still be orphaned at this day and age.

This will always be a possibility. Two blocks will always be able to be found at around the same time and when that happens, one of them will end up being orphaned.

[Tjopper]

You can click both blocks @ blockchain info and see which one ended up as a orphan and which one is in the mainchain.

However we decided to show it a bit different compared to bc.info. We would appreciate some feedback to see if this more clear or not.
https://www.blocktrail.com/tx/133a32ca9d5b2a9d7000d5a974e9a0548af2527d8d3c9a2fe56ba167ff46ed50

[wasserman99]

blockchain.info is showing that it was included in two blocks with the same block number with the block times one minute apart. It is likely the first block was orphaned, then the TX was confirmed in the 2nd block.

WoW, I didn't even know blocks could still be orphaned at this day and age.

This will happen at least once out of every 600 blocks on average. This is assuming that it takes exactly one second to propagate a block throughout the network which is not at all unreasonable.

EDIT: It will happen more often if the miner/pool is somehow misconfiguration or has a bad internet connection as it would take the miner/pool longer to send the found block out to the network.

[Game Sir]

Which platform do you do these operations ?

[MightyBTC]

I guess it's the problem with blockchain for sure.

[itsAj]

blockchain.info is showing that it was included in two blocks with the same block number with the block times one minute apart. It is likely the first block was orphaned, then the TX was confirmed in the 2nd block.

WoW, I didn't even know blocks could still be orphaned at this day and age.

There will probably be at least one orphaned block per ~4 days (more with many large mining pools - this is a separate discussion). Most people will likely not notice and post about them because they are likely not watching their TXs as closely as the OP was. (if he has waited less then a minute later then he would have seen that his issue would have resolved itself).