No, it's not.

The case Sony lost also relied on the end user having a blob of Sony's code. A user using their own key and a blob of Nintendo's firmware, which is the official stance of Yuzu on the correct way to do so, is exactly the same thing. There's nothing new to be litigated. Every part of Yuzu is very clearly legal.

The fact that it was used to play a game before official release straight up cannot possibly be relevant. It's a distraction. The project isn't, and isn't capable of being, responsible for anything but its own code.