MS Project automatically recalculates task durations when resources are added, breaking project schedules

Project managers using MS Project face a critical workflow problem where adding resources to tasks unexpectedly changes task durations, forcing them to manually recalculate and re-plan their entire project timeline. This behavior contradicts standard project management logic (adding resources should reduce duration, not change it unpredictably) and existing solutions require deep knowledge of MS Project's scheduling modes that most users don't possess. The lack of intuitive control over this behavior wastes hours on schedule rework and creates confusion across teams.