I'm encountering weird behavior with LW 2018 / 2019 transparency. I need to use a b/w gradient do fade off the visibility of several layers. But when I apply my B/W gradient alpha, the transparent zones are actually opaques, just not displaying the surface textures where there is transparency but the basic surface color. instead of transparency. I tweaked the ray recursion limits , refraction etc (the layers are just flat planes, no thickness). Also I'm using standard material, the layers are 100 % luminous and 0 % diffuse.
I had the same issue when making large clouds geometry ([planes) with transparency around the cloud, still renders black or basic surface color under the texture.
Never had this problem before LW 2018.
I can't use clip map as there is a progressive contour to my alpha / transparency image.