Jahn Teller Effect on Metal Complexes
If the orbitals of the metal core is distorted. the amount of splitting is not high enough to promote the pairing of energy. therefore the 2 electrons will go to two separate eg orbitals. let the splitting energy due to this distortion be β1. the electron in the lowers orbital will have an energy loss of β1/2 and the electron in the higher orbital will have an energy gain of β1/2 and therefore the net gain in the energy is 0. which does not give any additional stability to the complex(as there is no release of energy).
hence the distortion does not have a strong effect.