When you design your workflow, please to make sure all the actions are connected with the lines. If there are any actions are not connected with lines, you might receive the Node Incoming error message when publishing the workflow. The error message you will see would be:
This error means the "Set Content List" action with the name "Set Content List_2" does not have the incomine line. If you see this message, please go back to your workflow designer, find the action and check the condition lines.
You can see the example above. The line from the "Start" is not connected to "Set Content List_2".
To avoid this issue. please make sure every action has the incoming line (except the "Start"). When the line is connected to the action, you can see the border color of action becomes to "Orange". This means the line is connected properly with the action. Please see the screenshot below as an example:
You can also do a quick varification by moving the action, and see if the related lines are moving with the action together.