Often the successful performance of a project is problematic. The Lean Construction community has approached this issue by emphasizing variability reduction of the production process using the Last Planner System (LPS). In this context, we suggest that the variability characterization of managerial actions along the LPS process itself is an improvement opportunity. We used the concept of conversations from Linguistic Action Perspective (LAP) and the premise that the Bullwhip Effect (BWE) exists between the LPS variables to explore the variability impact of managerial actions during the LPS process. This paper reports the characterization of BWE of LAP conversations between LPS variables and its impact on planning reliability in five projects in the construction stage. Evidence collected suggests that BWE exists between the LPS variables and its existence may be related to the degradation of planning reliability. Although additional work will be required to corroborate these initial findings, this outcome seems useful to quantify management-efforts variability during the LPS process. It is expected that further exploration of these results could help to act proactively to prevent variability generation during the LPS process, where they can be used as a systemic-feedforward variables of disturbance related to the project social-domain.