This paper examines the consequences of a strong vibronic coupling on orbitally triply degenerate levels in a cubic environment for the three cases in which spin-orbit coupling is weaker than, comparable with, or stronger than the vibronic coupling. It is shown that vibronic orbital reduction factors may be strongly temperature dependent. The consequences of this temperature dependence for the interpretation of magnetic susceptibility measurements are briefly discussed. An Appendix details a method for the evaluation of overlap integrals between harmonic oscillator eigenfunctions.