Evolution of the Sun’s shape based on observations from four SDO/HMI roll sequences – for a linear Stokes polarization state (I+Q). The solar limb shape is approximated using low-order Legendre polynomials fit. The October 12, 2010 plot shows very large dips around 160 and 340 degrees. These values have been excluded from the analysis, and similar anomalies (due to sunspots or instrumental effects) in other datasets have been carefully filtered out to prevent them from impacting the overall results. The spiky periodicities observed, particularly on October 11, 2023, could be attributed to instrumental effects or minor issues with the spacecraft’s pointing accuracy. These periodic spikes may result from slight pointing deviations during data acquisition, which can impact measurement consistency. Instrument-related factors, such as sensor noise or calibration shifts, might also play a role. While these explanations are plausible, they highlight the need to carefully consider potential spacecraft or instrument artifacts in the analysis.