The rumor, as I heard it, was that Takeshi Obata of Death Note and Bakuman fame was the one suing her. The theory doesn't really hold much water. For one, as far as I remember, Hoshino-sensei was an assistant of Obata's so there's a chance that she received permission or even created the design herself in the first place. That's just theory. Barring that, though, the source of this information is from 2ch which isn't always the most reputable source. So far, there are no real and reliable sources to back up this statement, when the only statements from Hoshino-sensei herself seem to indicate that it's her hands again, and that Volume 18 is/was being worked on for its June release.
I don't think there's a lot to worry about. D.Gray-man is a pretty big cash cow for Jump, so if there was a lawsuit, it'd most likely be in their best interest to settle it quickly and quietly. Still, if this really was an issue of plagiarism, I don't see how the editors would have failed to notice it, so I highly doubt that plagiarism is the issue. :3
