If I do not specify any default nodes when configuring the Node parameter, then when I manually run the job, the dropdown list is still populated with a default node (I believe this is the first node of the available node list after the "ALL" entry).

Would like the capability of truly specifying "no default" (e.g., default node would be "NO_DEFAULT" or "NONE"). For this default case, it would be expected that the user would be forced to select a valid node from the list of possible nodes. Otherwise, if they left the default, the job would immediately fail. Ideally some error message informing the user that they need to select a valid node would be output to the console log.