Trucks disappear

Sulfur trucks just disappear from a super highway junction.
Other trucks can drive over the junction, except the sulfur trucks.
The trucks also aren’t existing anymore.
Edit: They also disappear on straight line super highways and it’s not only sulfur trucks but every kind of truck partially.

I have noticed that resources that are no longer needed disappear at junctions. Like when a housing building gets downgraded or a factory gets deleted.

That’s interresting. I’ve noticed that the Ademantine drill gets waaay more resources than it needs when it’s being constructed.
So perhaps when a building calls for resources, more resources get send out than it actually needs (not sure why) and than when the building no longer needs them, for instance when its internal storage is full, the extra resources which are already underway just disappear.