When a dual-port HBA fails with both ports in this configuration, the cluster behavior depends on whether the affected node is primary for the diskset.
If the affected node is primary for the diskset, Solaris Volume Manager panics that node because it lacks required state database replicas. Your cluster reforms with the nodes that achieve quorum and brings the diskset online on a new primary node.
If the affected node is not primary for the diskset, your cluster remains in a degraded state.