The degenerate 1 B 2 and 1 A 1 states with a triplet ground state occur from all calculations by MRSF, UMRSF, and U-SF-TDDFT at D 3h geometry. The relative singlet energy compared to the triplet by UMRSF and U-SF-TDDFT is lower by 0.1 and 0.2 eV than that of MRSF-TDDFT, respectively. The reduction in UMRSF energy is due to spatial orbital relaxations, while that of U-SF-TDDFT additionally comes from spin-contamination. These state energy lowerings appear across the entire surfaces. The singlet 1 B 2 state becomes degenerate with the ground triplet state at the 1 T L geometry, as the mixing of triplet contamination does not change its state energy.