Let me try to explain my line of thought-experiment, and let it be clear this is not what I think is going on. But it's possible:
Maui X-Stream makes an announcement stating they deliver an OSX emulator, that clearly seems to be a rip-off from Pearpc.
To not loose face after the hustle this announcement creates, they have to deliver something. So they contact the main Pearpc developer with an offer he can't refuse, him being an ill-funded student.
He then starts to rework and amend Pearpc so it can become CherryOS. While doing this he obviously can't contribute to the open source project.
So the reason for it is money, and maybe some extra resources for programming stuff.
Now I don't know if this is happening, it's all conjecture. And I mean not to harm or destroy anyones reputation by this.
PearPC is GNU/GPL (I think, could be BSD, eitherway the code *must* be published). Thusly they've got to fork over code if they're selling binaries (GNU allows you to sell the service of creating binaries, but you must also publish the source that created those biniaries). So if he's "amending" pearPC in the interest of gaining money from MXS, he's doing it illegally. Assuming it's GNU/GPL, then you can't change licesnes mid-stream with GNU. Once GNU, always GNU.