  A potential problem that may arise in the domain of distributed control
systems is the existence of more than one primary controller in redundancy
plans that may lead to inconsistency. An algorithm called NRP FD is proposed to
solve this issue by prioritizing consistency over availability. In this paper,
we demonstrate how by using modeling and formal verification, we discovered an
issue in NRP FD where we may have two primary controllers at the same time. We
then provide a solution to mitigate the identified issue, thereby enhancing the
robustness and reliability of such systems.
