600B grism (left) and 600RI grism (right) spectroscopic light curves with best-fit transit region shaded in grey. Left: the light curves appear to have very similar systematics with the exception of the top one or two light curves in which the region in the red box shows a small increase in flux at the end of the observation. This could suggest the presence of wavelength-specific systematics (WSS) in these data. Right: The slowly varying shape of the systematics – as highlighted in the red box – suggest that the ‘common-mode’ systematics are not actually common-mode but gradually vary in wavelength.