Eye of Winter - overlapping grounf effects

Does anyone know if Eye of Winter takes 50% extra damage from both different elemental grounds? Or are they always overwritten? From a visual point of view it looks like it only takes 1 effect at a time.

Example:
We have lightning ground + fire ground. I am not sure if they can overlap but lets assume that it just passes during its whole lifecycle on top of both grounds. Does that mean 50% extra Fire and 50% extra Lightning?

Doing some tests on my own I think it only cycles between 1 effect at a time.