...Ho-Oh? You must've played it a lot!
The only way you can get Ho-Oh w/o going to a Nintendo Event is by beating Mt.Battle in both the Colosseum and Story Modes after purifying all 48 Shadow Pokemon in the story mode, and I think it takes more than one play to do so... So I think it must be the MC being made by 3rd party... Either that, or maybe the game was made sometime before the white Memory Card 1019 was made(and the white Memory Card 1019 was made in 2005(I think), and that's 1 year ago), and thus, that very same game may also have some issues w/ Memory Cards that can hold more memory than the memory that the official MCs that existed at Colosseum's time can hold, and the only official MCs that existed at the time are MC 59 and MC 251, and any MCs that holds more memory at the time were all 3rd party cards that don't undergo Nintendo's initial testing process, so those cards may not be fully compatable w/ the Gamecube, as any product that doesn't undergo the initial testing process is an unlicensed product that isn't guaranteed to work on your game system...
You never know the consequences of using accessories to use games that use technology that's older than that of the newer accessory's time, but after the new accessory is made, games that are made after the newer technology can fully use it, while games made before the time of the technology's creation cannot use the new accessory to it's full potential, meaning possible problems w/ the game when it tries to access the newer technology when it really can't distinguish who it's made from: It always goes by whatever is available at the game's time, so in this case, it could think that the MC's made from a 3rd party organization, when that really isn't the case here, but who knows???