State writ of administrative mandamus is a substantive state proceeding, not merely a mechanism, and as such, is not subject to the Ex Parte Young exception to state immunity for federal remedies.
State claim that plaintiff had not exhausted judicial remedies by seeking administrative mandamus did not operate as a sufficiently unambiguous waiver of state immunity.
Denial of motion to dismiss is on exhaustion grounds can be appealed as a pendent matter.
http://cdn.ca9.uscourts.gov/datastore/opinions/2018/06/06/17-56110.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.