I just requested a withdrawal from a site, and according to blockchain.info the withdrawal has many confirmations, but one of its inputs is unconfirmed (as indicated by the red 'U'):
That's meant to be impossible, so probably indicates database corruption at blockchain.info.
Here's a link to the tx in question:
https://blockchain.info/tx/02248ff5fe93483473f1c48baf7b23ac342ddb510ffba1e865d82e4272cf6548
It is definitely a bug at the blockchain.info site.
blockchain.info displays the following transaction as unconfirmed:
https://blockchain.info/tx/0073a622ad48d45883273478bf2de99db64af6aa25341a8aefd5f109b064007c
But according to my Bitcoin Core, that transaction has more than 100 confirmations. blockr.io confirms what I am seeing in Bitcoin Core:
http://btc.blockr.io/tx/info/0073a622ad48d45883273478bf2de99db64af6aa25341a8aefd5f109b064007c