If the mod is activated for existing maps, the loaders are not craftable (or even shown in crafting popup). They only appear after the specific logistics research.

In my case:
I started a new map, played some time on it and then activated the mod. The yellow loader is not craftable but after researching logistics 2, the red loader appears in crafting screen - but the yellow don't.

Is it possible to fix it?

Could you send me this map? It's possibly a migrations issue, in which case I'll need to investigate it.

Though that seems odd. Hm. I'll see if I can reproduce following your steps with a new map.

Repro'd. It's a migrations issue, I'll figure out how those work and fix it. Should be reasonably straight forward, just need to reload the techs.

Fixed and pushed the update.