Mod version 3.5.4.3
Is this behavior with stacking auroras an undocumented part of the 3.5 update, or is it a bug? I've seen two as well. If it IS a bug I would like to request it be permanently built in because they look nice.

Nope - not a bug. Every night there is a chance of 1-3 bands with different coloration.

Thanks for the information, closing.