Water puddles are not compatible with shaders or at least they are not getting detected as a water source so they don't get the shader water effect or a water sound when walked on.

For the Kappa shader, extending the

block.10001=water flowing_water

line in block.properties to

block.10001=water flowing_water subwild:water_puddle

worked perfectly. Perhaps the same fix can be done for the rest as well.

Does the shader file have a way of adding liquids to the whitelist similar to how waving leaves work?

If so, this would be something that the shaderpack author may need to add by default on their end (whitelisting subwild puddles)

What you say might be correct but I think that it doesn't work mostly because what the mod ads is a completely new block and not a liquid with the same properties as water, hence why it doesn't get detected as such (it is a new block without connected files to the vanilla water so it doesn't get effected). Even if what you said could be true it still a problem on this end and not theirs, after all, for the problem to be fixed like that, every shader pack would need to change the code just for this mod. Not really efficient.

@disastercube try filing a cauldron or for example some mekanism cables with water. Do they have the shader effect? If not, I don't know if theres much I can do

Cauldrons don't get effected by shaders at all but that is just how it always was. No shader effects water inside cauldrons. I tried many more shaders and so far there actually was one compatible with this mod, the "SEUS ptgi ray tracing shader". Also, water inside cauldrons is different even in vanilla. They don't posses the same abilities nor the texture of normal water (they don't have an actual water source). I really don't get it why you mentioned a cauldron as an example ?

The only compatible shader "SEUS ptgi ray tracing shader" example:

@disastercube i mentioned the cauldron because on a technical level its similar to the puddle. It has more in common with the cauldron than a water block - it's just an arbitrary block using the water texture. The puddle is not a water source or even a fluid. It's a block like a carpet. And as you can see, it looks like most shaders are just coded in a way that doesn't support blocks that use the water texture like cauldrons or in this case puddles

Works with the shader i use, not as good as main water, but it has some shader effects applied to it.

https://www.curseforge.com/minecraft/customization/complementary-shaders

Shader plus resource pack.