In this paper, we report a peculiar movement of the beam cross sections associated with both the diffracted and undiffracted laser beams from a liquid crystal spatial light modulator (LCSLM). The beam movement becomes noticeable when the beam position is monitored continuously for several hours. We perform experiments to show that the beam movement is non-mechanical in nature and is connected with the power on/off instants of the LCSLM as well as the heat conductivity of the mounting slab which acts as the rigid support to the LCSLM panel. We also present a detailed analysis of the experimental findings to ascertain the possible cause of the beam fluctuations.