From what I read, it’s not a bug.

Many bulbs trade on the green LED for more variation in white. Red/Blue serve a function to make whites warmer or cooler, green has no such function.

And because most people use white, they ditched the green LED. That’s why the green it has is more yellowish than you would expect.

It probably also means the bulb API has no dedicated green setting, which is why the remote and 3rd party apps don’t have proper green settings.

It’s a bit of speculation though, not entirely sure. Apparently older Hue bulbs also do this.