I deleted the Station 2 (Combiner) and dragged a combiner from the library into the model. I reconnected the objects. And surprisingly the model behaves correctly or in other words the error doesn't occur anymore.
The DP60 contains a weird logic, which sends the items on the above conveyor to the Station 1 or 2. Frist all items are send to the outobject at port 1. Then at the second condition the items are sent to outobject at port 2 if the content of the Station 2 is exactly 1. In my opinion there is a custom code necessary:
if (model().find("Combiner1").subnodes.length==1) {
treenode newDest = current.outObjects[2];//Station 2
Conveyor.sendItem(item, newDest);}
else Conveyor.sendItem(item,current.outObjects[1]);}//Station 1 I used instead of the content or the statistical content property, the subnodes.length property.
The standard picklist option doesn't contain a structure like if .. then .. else .. there is just the combination of two conditions possible. Then it is important to set them in the right order.
Additionaly there should be a logic that lets pass only one item to the Station 2, if the combiner contains the tote. Otherwise there builds up a queue of items on the above conveyor in front of the second exit transfer and only sometimes the condition of DP60 becomes false, so the Station 1 receives items again.
