I'm in a game of World Domination IX. I had fleets in West Atlantic and Southwest Atlantic. Recife is unoccupied, and I had an army in Buenos Aires. I originally ordered my fleet from West Atlantic to Recife, and ordered the army in BAi to hold. I clicked "ready," but I changed my mind. I clicked "Not ready" and then ordered my fleet in West Atlantic to convoy the army from Buenos Aires to Recife, and ordered the army to move there via convoy. I tend to be pretty careful about orders, and I'd swear that's what I entered before the save. So, perhaps there was a bug in the orders reverting. By the FAQ, though, that almost never happens. Maybe I screwed up. If I did, though, that presents a different bug.
I have a fleet in West Atlantic and one in Southwest Atlantic. I have an army in Buenos Aires that I want to convoy to Recife, which is unoccupied. For some reason, the orders were to convoy the unit from BAI to SW Atlantic, and attempted to go directly to Recife to there. Clearly, that's impossible. There's absolutely no way that can work, but the game allowed the orders to go through. That's similar to me ordering my army in Deep South to move to Alaska. If I screwed up my orders, which is possible, the game should not have even allowed me the option to screw up the orders in that particular manner.
game: http://webdiplomacy.net/board.php?
gameID=40701#gamePanel
Possibly related thread: http://forum.webdiplomacy.net/viewtopic.php?f=9&t=120
Also possibly related: http://forum.webdiplomacy.net/viewtopic.php?f=3&t=431