MTGox has continually thorough the shutdown made a small number of what appear to be dust-cleanup transactions. Thats all these appear to be...
Ironically, someone of them like TXID: ed7ffa58fef651adaf1281ad10e98a4399eb2be40950345c7ccb7c8f76f067e1 in their liast are spending immature coinbases (45d45286bac04311684ab7716ab170b50781cde6b094d9a644fb89ca07ae6888:31 is a coinbase with 67 confirms as I write this) and so it's not a valid transaction. So even after all this time and weeks of outages for fixes MTGox is still producing invalid transactions.
The ntxid field is somewhat new, I first noticed it there a week-ish ago.