@BlueMountainsIO - just an update on this - it appears that depending on how the PAK files are packaged and later loaded in, your plugin doesn’t load in the shaderCodeLibrary correctly when the PAK is mounted. This may be a product of the PAK packaging process (we’ve found that the PAK file that’s produced is missing the uplugin file in 4.27.1 which could be the issue?).
In any instance, it could be worth incorporating the following function into the mount PAK node to catch this (as a workaround, we’ve just implemented this ourselves in our own BPFunctionLibrary):