As I was detailing my map, I discovered that ANY decal was not working with any of my custom models.
They would not stick to the models at all as if they were not there. I tried to use the shader in unity (Standard Decalable) with no luck. I even hit up Spyjack for info on why this could be happening, and he told me to add “Asset bundler version 2” to the model’s .dat file. This changed nothing outside giving it a strange white filter over the model as if it was a ghost. This also did not change if the decals worked or not. This also applies to workshop decals as they do not work either.
Also note that this only applies to MODELS, as far as I know the decals do work on custom roads and materials.