Been modeling this glass for a poster and having trouble with some shading in the water. It was fine but I think it happened when I smoothed out the liquid, it may also have happened when I set the max transparency to 12. I am not sure since I am relatively new to Blender (two weeks).
It’s worth noting that to get a realistic looking water shader, you will need an environment for the water to reflect. I recommend using a HDRI as your world lighting in order to get nice looking reflections.
Yeah thats simply because you have the transparent and glass shaders in the wrong sockets. Switch them around and it will work.
Currently you have the transparent node plugged in at the top, it should be at the bottom.
Also make sure that when using a HDR image as your world, you use an environment texture input rather than an image texture input, this will map the panoramic image 360 degrees around the world. And turn on “multiple importance sample” and set it to a decent resolution i.e 2048 or 4096
And a little tip when using HDR images, the node setup shown below is a better way of controling the strength of the image emission, it ensures that the brighter parts of the images are increased in strength more than the darker areas, giving you more realistic lighting.