I have to quibble with your headline.
The sovereign immunity gambit was seriously questioned but ultimately not decided on. Everything the judge said on that would appear to be completely obiter.
The court agreed to join the Tribe (in case the assignment was valid) and left the issue of whether the assignment was valid or invalid to be decided in the IPR proceedings.
Since the patent was itself held to be invalid, that is now presumably not going to happen.
The patent judgment makes interesting reading if only to note how weak the basis for claiming the patent to be valid seems to have been.
