I am not saying that you are wrong in your optimism, however as you mentioned, "They had announced this maintenance through their twitter feed several hours before it happened and the site went down as expected". Several hours notice is not scheduled maintenance, but more like a major fire.

While pulling the plug is sometimes the best option, it implies a real issue. It seams to me there would have been a contingency where trading is stopped to reduce load and isolate systems, while account balance and wallets are available to move funds.

However it is possible, as advertised, this is a bug that did not show until it was launched on production. It seems you would put the system back and work on it in the development environment.

I am leaning towards database corruption that is compounded by backups that do not reflect the stable state. It is possible backups are corrupted with how long they have been running at max capacity. They might eventually get it right, but wow what a headache for the team working on this. Obviously not much fun for the users either.

I have not looked, but if they have been hacked, seems the transfers would show on the ledger.

Time will tell. Thanks for the article!