It appears the yellow is more visible in the yellow elephant collins. The printer may have over laid the white elephant with yellow ink causing this. Since the "Yellow Elephant Emblem" seems to be found on Pied.25 backs only so far I would say this is another Variation to add to the set. If anyone can provide proof or reasoning why it is not I would love to hear what your thoughts are.

BTW Turner great job on the Collins research and glad to help you out with what I can. Hope to hear from you soon buddy. Be well.