Same as Fig. A.1, for Visit 4. Brightness scale factor b = 90. The modelled brightness ratio of the components inverts between visits 2 and 3, reflecting either rotational variation, or the uncertainty of the fitting results due to image noise and thermal breathing of the PSF. The conservation of the total flux makes a rotational cause less likely, as it is unlikely that the apparent cross-section of one component increases at the same time and by a similar amount as the other decreases.