Not exactly. The buggy wallet software, used by these exchanges, identifies transactions by their hash. Even if one of the duplicates is confirmed, the buggy wallet still thinks the other is a new transaction, because it has a different hash.
The fix is checking all inputs/outputs rather than relying on the transaction hash.
MtGox is the only one using the TXID hash to track unconfirmed transactions. The problem with the other wallets is that if you try and spend a change address from a rewritten transaction before it is confirmed then that transaction involving the change is then invalid.
The fix is checking all inputs/outputs rather than relying on the transaction hash.