Warm, vanilla,spice,sexy,wears well & long. Always complemented on fragrance & asked what it is. I've never noticed any bottle being different.
It has nothing to do with the reformulation. The notes listed are the ones that are obvious. Different formulations/concentrations like perfume and EDT bring out different notes.
I believe that Guerlain has reformulated Shalimar many times over since it's creation in 1925; the difference listed here on Sephora might just be an error, or it could be a listing of the current formulation.
The fragrance notes of original Shalimar are; Bergamot, Rose, Vanillin, Civet, Musk, Incense and Jasmine.
They are forever tweaking and changing Shalimar, but if you want to experience the true incense, animalic, vanilla beast that is Shalimar; I'd recommend vintage perfume. Hope I helped!