FS22 | AI not pulling slurry from Barn or Tank

[NordicTaurus]

The problem is just it says on the lable. I'm trying to get the AI helpers to draw slurry from either the barn or from a liquidmanure tank. When I start the helper he just stops and sayst I need to refill. Even though the spreader is full.

I've googled this a bit but not found any obvious cause for this, I've also used this method before without any issues.