Correlations in the Lyman-α forest flux across redshift. Top row: Correlation matrix for observed QSO sightlines, showing a positive correlation (in red) in the off-diagonal terms near the diagonal at all redshifts, and an increasing correlation length at higher redshifts. Bottom row: Mock sightlines with continuum-reconstruction uncertainties applied, leading to a slight increase in correlation at lower redshifts, while failing to account for the observed correlation at higher redshifts. First column: Correlation matrices. Second column: Standard deviation of the correlation matrices. Third column: Statistical significance of the correlation, estimated as the ratio between the correlation matrix and its standard deviation. The results suggest that while continuum-reconstruction uncertainties contribute to correlations at low redshifts, they cannot account for the correlations observed at higher redshifts.