Virtual reality (VR) is found to present significant cognitive challenges due to its immersive nature and frequent sensory conflicts. This study systematically investigates the impact of sensory conflicts induced by VR remapping techniques on cognitive fatigue, and unveils their correlation. We utilized three remapping methods (haptic repositioning, head-turning redirection, and giant resizing) to create different types of sensory conflicts, and measured perceptual thresholds to induce various intensities of the conflicts. Through experiments involving cognitive tasks along with subjective and physiological measures, we found that all three remapping methods influenced the onset and severity of cognitive fatigue, with visual-vestibular conflict having the greatest impact. Interestingly, visual-experiential/memory conflict showed a mitigating effect on cognitive fatigue, emphasizing the role of novel sensory experiences. This study contributes to a deeper understanding of cognitive fatigue under sensory conflicts and provides insights for designing VR experiences that align better with human perceptual and cognitive capabilities.