preburst light curve showed a modest upward trend. If we fit this trend with a linear function, then we find that the burst rate decayed to the extrapolated intensity at $t\simeq580{{\rm\,s}\xspace}$. ]{}

Two unusual features stand out in the burst light curve (Figure \[fig:lc\]). First, it shows a pronounced double peaked structure, with a local minimum of $\approx15,000$[ct[s$^{-1}$]{}]{}at $t\simeq13.1{{\rm\,s}\xspace}$ and a secondary peak of $\approx16,500$[ct[s$^{-1}$]{}]{}at $t\simeq15.5{{\rm\,s}\xspace}$. While double-peaked X-ray bursts have commonly been observed, these structures are usually caused by PRE: the temperature of the photosphere temporarily shifts out of the instrument passband, causing an apparent dip in the observed X-ray rate [@Grindlay1980]. Given its low-energy coverage, [*NICER*]{}is able to follow the temperature of the photosphere throughout the PRE phase, so any observed dip in the light curve is likely due to a dip in bolometric flux [@Keek2018b; @Jaisawal2019]. We investigate this in Section \[sec:time resolved\].

Second, there is a noticeable pause during the rise to the first peak. Initially the flux increases rapidly; however, between $t\simeq0.6{{\rm\,s}\xspace}$ and $t\simeq1.3{{\rm\,s}\xspace}$, this rise briefly stalls, with the count-rate remaining constant at $\approx13,600$[ct[s$^{-1}$]{}]{}. After this pause, the rate continues to increase toward the maximum, albeit at a slightly slower pace (Figure \[fig:lc\], inset 