Not the original commenter but I am in the industry, and its true, many satellites shut down during this region over the South Atlantic.

For that reason, it is not a popular orbit unless there is a larger driver behind the selection. For example the ISS goes right through it in order to be above Russia for a reasonable portion of its orbit. I believe Astronauts have reported increases in optical flashes during this part of the orbit as more energetic particles pass through their eyes.