Hurricanes are considered unlikely to occur over the South Atlantic because wind speeds between upper air and lower air are very different(*); this also applies to this case.
It seem that a temperate cyclone changed and developed into a tropical cyclone. Scientists question whether this cyclone can be defined as a regular hurricane or not.

(*) The conditions for hurricane generation are a sea-surface temperature exceeding 27 degrees (except near the equator), a small difference of air temperature between north and south, and a small difference of wind speed between upper and lower air masses. Low latitude sea areas, excluding the South Atlantic and South Pacific near Peru, generally satisfy these conditions.

Figure 2 depicts the three-dimensional rainfall structure acquired by PR observation and precipitation along A to B in Fig. 1. The top of the rainfall isn't so high, about 8km, but you can find intense rainfall areas (red, yellow and green) outside the eye in this figure.