What term refers to employee behavior that requires immediate corrective action by a supervisor?

The term that best describes employee behavior requiring immediate corrective action by a supervisor is "actionable item." This term specifically denotes a situation or behavior that is significant enough to necessitate prompt attention and intervention to correct the issue. It indicates that there is an actionable measure that needs to be taken to resolve the matter at hand, making it clear that the behavior cannot be overlooked and needs to be addressed rapidly.

In contrast, while a "warning item" may suggest something that requires attention, it does not inherently convey the urgency or clear call to action implied by actionable items. An "advisory note" typically serves as gentle guidance, suggesting improvements rather than demanding immediate corrective measures, and may not reflect behaviors needing urgent action. "Performance issue" can describe a range of problems but does not specifically imply that immediate intervention is required, as performance issues may allow for a longer process of evaluation and discussion before corrective action is taken. Thus, "actionable item" is the most appropriate term in this context.