as far as i know, task-nodes are used to assign tasks to human actors. tasks are actions, which must be executed by a person.
Nodes are used to execute actions by external systems ( it-systems) e.g. a database update....
no human person is involved.
an other difference is, that the node is no wait state ( unlike the task-node ).
that means, that the processinstance execute the list of actions, which is defined for the node and direct leave the node. Therefore, you must tell the processinstance in one of the actions, which transtion should be taken ( node.leave("transition")) otherwise, the default transtion would be taken.
I hope, i could help ( i know, my english is awful)
sorry, i have to correct my posting.
you must call the exectionContext.leave("transtion") method in the activty action handler to leave the node....