Stuck at dropoff point?

[tsbertalan]

I'm using AD (with CP) on the popular "No Man's Land" mod map. I have a combine unload loop to bring grain (canola ATM) down to the built-in selling point in the center of the south edge of the map. My tractors bring the grain there, unload, and then never return to their waiting point. Instead, they remain sitting on the selling point, with its waypoint name still highlighted green in the AD UI, until I manually click the continue >> button.

I've tried jiggling my path nodes around to make sure there isn't a particulary sharp corner required after the dropoff, and changing the "silo empty" action to both options.

Any ideas for why it might be stuck?