I'm using a warehouse to split Geodes in Sea Block. Regular loaders going in, filter going out. It works great with blue belts but when I upgraded to turbo (purple) one side of the belt runs at normal speed and the other goes quite a bit slower (I'm guessing 15-30).
I thought it may be too many loaders at once or something similar so I used the console to spawn ultimate (green) loaders and they work correctly.
Here is a picture of the setup the malfunctioning loaders are the ones with nothing on the belt. https://i.imgur.com/EeRS3CA.jpg