AAI Loaders, expensive version is not stacking?

Hello,
I have used this mod previously with Space Age on the lubricate mode, and the items would stack to 4 tall on the conveyors (with research done), but with the expensive version, they are not stacking once I have completed the research. I have tried removing them and re-adding them just in case, and reloaded the game, and as you can see in the image, the stacking is working fine with inserters.

Just to be clear, this save is running on a dedicated server, but I have tried it in single-player mode too.

Happy to send any extra info, just let me know the best way to do so. The game save is around 45mb right now.

Thanks
Ian