Hi Danil, NDVI values shouldn't be between (0,1) as you said. They are always between [-1,1] where values greater than 0.2 are considered vegetation, 0 usuallly for bare soils, while clouds and snow fields will be characterized by negative values of this index.

Your values are ok but you have to be careful with pixel with clouds (S2_QA60 band)

I hope it helps

Ernesto