What is wrong with this btc Address or Blockchain

[BNO]

Hi,

This address:
12PTTP9vAaHEP8LrYRnLwPtWZALr1Zwx5c

was created with mycelium wallet. But something magical (to me at least) seems not to be right with it. When i tried yesterday to send some btc from bitstamp to it it failed.
Yea i know the stresstest. But now i think that wasn't it. If you check this on Blockchain you get "invalid checksum" WTF!!!
But it gets weirder, if you go to blockr. io it says that everything is O.K. with it, just like mycelium wallet app which created it.
So on the one side is Bitstamp and Blockchain saying this is not O.K. on the other Blockr.io and mycelium saying everything is o.k. with it.

I deinstalled myxcelium reinstalled it, created a new wallet address:
18MXoqNgx6hiNBbAEd61udyQASxS9CbAVn

With this address everything is O.K. and i was able to send money from bitstam to it.

My motivation is now to understand what happened here. Did Mycelium create a wrong address or how come that 2 Parties are not accepting those adresses The thought that i have some funds in an address and they can't be withdrawn because "something" is not right with the addresses generated is pretty scary for me....Maybe somebody knows something about this

EDIT: I posted yesterday about this https://bitcointalk.org/index.php?topic=1176454.0. But the scope of the thread was more on stress test and fee market as explanation why transaction didn't go through. But since today the second address in mycelium did work just fine but the first one still is shown as "broken" by blockckain, i see this in a different light now... It's something wrong with the address, and thought it would be better to discuss this in a new thread here, to not mix that up...

[odolvlobo]

That is not a valid address. It is unlikely that it was generated by Mycelium, but there is always a possibility of a bug. It is much more likely that you made a mistake copying it.

I tried sending to that address using Mycelium and it was rejected, as expected.

Blockr.io accepts invalid addresses. That is annoying. It probably doesn't verify the checksum.

[BNO]

I really checked this 5 times yesterday... to be sure.. Still there could be the chance that maybe a letter got misread from me. (something like a 0 with an O or so)...

So to understand the process: so the wrong address got into Bitstamps tx than the first node that got the tx (which had more than just my tx) checks all the single addresses, rejects that one output to the wrong address but processes all the other correct outputs, or how is that done then?

Edit: since i did not lose the 0.1 btc which i then sended to the assumably wrong address.

[blodeux]

hopefully your funds will return to your account, as they cannot go to an invalid  address

[odolvlobo]

So to understand the process: so the wrong address got into Bitstamps tx than the first node that got the tx (which had more than just my tx) checks all the single addresses, rejects that one output to the wrong address but processes all the other correct outputs, or how is that done then?

A node rejects the entire transaction if it is invalid. A node cannot modify a transaction (beyond transaction malleability).

Bitstamp never tried to send the bitcoins. It is not possible to send to an invalid address in a transaction. If Bitstamp did send the bitcoins, they would have gone to a valid (but incorrect) address, and Bitstamp would have debited your account.