Yanero v Davis further gives a clear list as ready-reference to ALL of the citations regarding immunity, and it becomes clear in the analysis of these many and varied case law citations that the singular basis for immunity is discretion. If this were not so, the powerful would always win every ruling, because the powerful would always be able to litigate against the official decisionmaker at a lower opportunity cost to themself. Fairness follows closely on the heels of discretionary immunity, but remedy for actual wrongs done by an "official" must also coexist with the necessary immunity which necessarily protects us all.
The Board of Claims was rightly involved in matters which did not fit under the umbrella of state-confirred immunity such as those failing to follow law, duty, ministerial task - etc., but now appears by this correct analysis to have crossed a constitutionally-clear inhibition.
At this moment the public awaits the legislative response, which must be forthcoming.